Can Individual cells feel pain ?

Question

or only nerve cells, or cells in the nervous system or what ...?

what cells can and which can't ??

Answer 1

Individual cells (neurons) have receptors for pain, but they do not "feel" it the way you mean.  The neurons fire action potentials, which send signals to the brain, which interprets the signals as pain.  Thus, no brain, no pain.  (For example, a pithed frog (one with its brain destroyed) while still "alive (its heart is still beating), cannot feel pain.