For about a month and a half, I have been having lower left abdominal spasms. It feels like a muscle spasm, only it is inside of me, and it will come for a number of days, and then subside for about 2 days, then come back. It isn't painful, but a very weird sensation. I am in my mid teens, and I am not pregnant, not sexually active, don't smoke, don't drink, don't do drugs, and I am a cross country runner. Does anyone have any idea what is wrong with me??

I have that sometimes in the morning I think it's when like your muscles are getting warmed up.