H.K.
I had something similar when I was preggers. However, mine was on the left side and it felt like whichever organ was being squished up into my rib cage was going to explode when I took a breath. It wasn't constant, I felt it a few times a day and especially while laying down. I told my doctor about it and she just kind of blew up off saying it was normal. It was VERY painful. Here's the weird thing... my son was born ten months ago and I had that same exact feeling again the other day. All of a sudden I couldn't take a breath, it felt exactly like it did when I was pregnant. Now I'm freaked out!