I am a 28 yr old female. I have been having random, painless but very obvious pulsating on my left ribcage (it feels like a flutter). I say on , because it seems to be surface and is visible, as an eye twitch. This would lead me to believe it is a muscle spasm. However, I m concerned that if it is Not, it should be checked out (although I don t have insurance), as it could have to do with my intestines. I ve experienced gas that felt similar, but this is way higher than any gas I ve ever had. For background info, I have always suffered from low iron, and lately have had higher blood pressure. I smoke and have been drinking more lately. Very stressed.