Strange pain

I’m having this weird pain like at the bottom of my ribs where my diaphragm is. It’s a really sore or tight muscles. It usually only hurts at night after a stressful day. At first I thought it was a stomach ache but it’s coming on and off. Could it be a side affect of pregnancy or the c section? Could it be my abs have stretched too much? (I’m 5’1) Help!! I’m in serious pain and meds aren’t working either