Blondie,
If it were your appendix, you'd know it! You would be doubled over in pain. If you are female and it is mid cycle, you could have ovulation pain. I know this because I went to the ER doubled over in pain and they thought it was my appendix until they did an ultrasound and found that a mid-cycle ovarian cyst had ruptured (this was nothing serious - it just hurt like crazy). Before it ruptured, I just had mild pain for a few days. But like you said, you probably pulled a muscle, silly!!! If you can still function, then it is probably nothing. If it's still there in a few days, call your doctor.
