Pain in abdomen

I’m in week 15 of my second pregnancy. (First was 4 years ago) I have pain to the touch on the right side of my abdomen. It doesn’t hurt unless I do touch it (some may say “just don’t touch it”), but I was just rubbing my belly one day, and noticed how tender this area is. I can feel something firm there, I’m not sure if it’s my uterus or bladder, but when I say tender I mean just barely palpating it hurts. I have an appointment Thursday so I plan to mention it then, but just curious has anyone else experienced this?