Runs Fast

Question

My Tag Heuer Aquagraph has recently been running fast. It's automatic so I'm unsure what the problem is.  It seems to gain 5 mins every 2 or 3 days. By the time a couple weeks go by, it's about a half hour too fast. What could be the problem? The last thing I could remember that would have affected anything was pounding on a door with the same hand that the watch was on. The watch did not hit the door but maybe the force could have transferred from my arm to the watch and affected the internal mechanics or rotor? How much would it cost to fix something like this?

Al