I did go to the Dr. and found out it was a blood clot in my lung on the other side :(
I think you should get it checked out I am thinking it sounds like a gall Bladder pain, it can be under your right rib radiating up into your shoulder and arm,and into your back, it is to do with eating and diet, dont drink milk or any high fat foods, do not eat later at night, if you think it could be this... google Gall Bladder it will tell you more, also what foods to avoid that could trigger it ..Good Luck