Why does your arm hurt after a shot is given?

Question

I got a tetanus shot today. I knew my arm would get sore, but why does this happen?

Answer 1

Celeste, the answer you received on your flu shot question was an excellent one.  Two thumbs up for the person that already answered it correctly (this humble approval coming from a nurse/paramedic that often wondered the same thing).  ***The real reason I'm here not to answer the above question, but one you asked earlier.  I googled the same question just today, and thought Yahoo answers would be a decent source of answers, but many of the folks that answered your question about whether or not it is better to turn off your Air Conditioning during the day gave nonsensical answers based on anecdotal evidence (what they themselves perceived and thought was best for them based on their own very limited experiences).  I believe that the best answer to your old question is A. It is ALMOST always better to turn the AC OFF when you leave the house for several hours, as it SAVES MONEY/ELECTRICITY PERIOD.  But, never say never or always...  Read on my precious, and you will see why that saying is so true in this case. . .  B. If you really can't stand returning to your house which has now become really warm/humid, and possibly even a lil smelly (odor causing bacteria LOVE warm/humid places) for even a few minutes, then wasting AC power by leaving it on all day may actually be best for you.  For example, like if your Moms is coming over, and you don't want her to know your pad gets a lil stinky on super hot days, or that you forgot to do the laundry for like a week. . . you might want to spend the few extra cents it will cost you to keep the air moving (fresh), and cool with the AC unit.  Not a common occurrence hopefully, esp. now that we're all so energy conscious, but hey save a little here, take a little there.  Right?   Here is the really long and technical (BUT CORRECT) answer from Michael Bluejay, who is a really nice, smart guy, who specializes in how to save electricity. . . (you can find him quick if you google his name).    QUOTE::: "It's a myth that leaving the AC on while you're away at work uses less energy than turning it on when you get home.  Here's why:

Heat goes to where it's not. That's why heat from outside goes into your cooler home. With the AC off, at some point your house will be so hot it can't absorb any more heat. When you come home and turn the AC on, the AC removes all that heat.

But if the AC is on when you're gone, then you've turned your house into a heat magnet. But keeping it artificially cool, there's no limit to the amount of heat it can absorb. It can always absorb more heat. And your AC has to remove that heat constantly. Your AC kicks in and removes some of that heat, then the house is cooler so it sucks in more heat from outside, so your AC kicks in again and removes that heat, and so on.

This means that throughout the day, your house has absorbed way more than one houseful of heat. And your AC had to remove it all. By contrast, with the AC off all day, then it has to remove just one houseful of heat when you come home and turn it on.

Let's say you leave the AC off, and your house absorbs 20k BTU's of heat and then stops, because that's all it can absorb.

Now let's say that you have the AC running instead. The house absorbs 5k BTU's of heat, so the AC kicks in and removes it. Then it absorbs another 5k BTU's, and your AC kicks in and removes that. Repeat that process several times during the day.

The actual numbers will vary, and I haven't tested this to see exactly how much the penalty for leaving the AC on during the day is, but there is zero question that running the AC all the time uses more energy than turning it on when you get home. This is not a gray area, it's simple physics, and no person with any knowledge of this subject disputes it. Running the AC when you're not home wastes energy, period."  Celeste, if all that seems too complicated (I had the read the whole thing a couple of times myself), think of it this way. . . If the AC is running all day, it is constantly battling heat that is always leaking into your house.  If you turn the AC off during the day, it takes a little while for the AC to win the initial battle with the heat, but you still spend a lot less energy/money to get your pad back down to cool.  Your probably already a pretty cool person, you can tuff it out for a few minutes right?  Even the rather large house me and my roomies share only takes about 20 minutes to cool down from the hottest (100 Degree plus), days here in Texas.

*******

Sorry 'bout the bandwidth (long-a$s answer), but SOME of the answers you got before were so FAR OF BASE. . . I couldn't let them influence you.  Yahoo rocks!  Wikipedia rocks better (probably one reason Yahoo has a link to Wiki right on this page. . . .  Getting information from more than one website may be in your best interest at times. . . deciding when those times are will greatly affect the quality of your life.  I hope you make great choices all the time, and have a great one!

Answer 2

because sometimes the chemicals from the shot (depending what's in it) can irritate the muscles or tissue around the shot area. for instance, HPV, Tetanus and chickenpox vaccines all cause mild forms of irritability in most people.