Extra Long Recovery Time...

I work out a few times a week mostly on my arms, after all my works outs my arms KILL or at least 4-5 days. I was thinking what the reason could be for this and this is what i thought of:

-overworking my muscles?
-not eating properly?
-not drinking enough water?

I stretch before I work out 99% of the time, work out properly (meaning proper movements and form) but i was wondering if someone can help me out with this and telling me what can help.

-Js