Pain in my rib cage

I have been having pain in my rib cage, on the right side. I was really worried that I had hurt myself at the gym last night because I did some moves that made me feel very uncomfortable afterwards.

But I did some research and it seems it’s normal for pregnant women to have that particular pain. It is the result of the uterus moving upwards in the body, the rib cage expanding. Why am I having that pain before my 3rd trimester and why only on the right side (most women experience this on that side too) ? I don’t know.

It is really painful at times but I know it will go away after I deliver so…