Pain low in my abdomen

[Halafel]

It's about half way between my belly button and my side, below my tummy, but not quite as low as my groin.

I do a lot of yoga, pilates, some weights and some running, so I guess most likely is a muscle strain, but how do I know?

I'm not in agony, but it's been lingering for a few weeks now.

Abdo pain is hard to diagnose. Which side is it on? Any other symptoms (I am not a medic, just nosey)

Appendix?