Mid to lower left abdomen localized pain?

This Pain could be from a muscle that has been over used. Constipation can sometimes cause pain in that area. Make sure you use a fiber supplement twice daily to keep the intestinal tract flowing. If the pain continues see your medical doctor for a complete check up.

"In most people, the appendix is located at the lower right quadrant of the abdomen. In people with situs inversus, the appendix may be located in the lower left side.

Situs inversus (also called situs transversus) is a rare congenital condition in which the major visceral organs are reversed or mirrored from their normal positions."

Got that off of Wikipedia, just so that everybody would know that with most people the appendix is located on the right side of the body. So I think we can probably rule out the appendix for you.

Since you said you were a male, really the only thing there is intestines. I would go to the doctor and get checked out.

are you male or female?? if female it might be related to your ovaries, you might even have a cyst. you should go get checked. some come and go but there are some that can stay and get larger, wicj causes more pain, that have to get surgecly removed

True enough, my mother's appendix was on her LEFT side.