Hi Doctor: I Have This Occasional Pulsating Sensation On The

Hi Doctor:
I have this occasional pulsating sensation on the left side (upper outer quadrant) of my abdomen that started last summer. It's more of a tickling feeling than a pain. About three weeks now, I started feeling this heaviness on my left flank and a pea-like lump on the same area. Sometimes I feel uncomfortable lying on that side, which is usually my preferred position. Is this something I should worry about?