For A Couple Of Weeks Ive Had An Ache On

For a couple of weeks ive had an ache on my right side, under the armpit where it meets my breast. It comes in goes. I cant feel any lumps or bumps just the ribs but it is tender to the touch. Ive notice too that i sometimes have an ache in the same side back shoulder blade area. It doesnt really affect my activities its just really uncomfortable when the ache is there. How worried should i be about this?