stress?

If it gets to a point where it's constantly bothering, I'd go get it checked out. You can probably go to your local pharmacy and they'll explain a few things to you. I think it may have something to do with your eating habits, daily living, stress, etc.

Probably stuff you can control on your own rather than needing medication.

I notice that I sleep a lot better when I go work out or exercise or do something physically exhausting that enables me to basically crash out once I lay down in bed.