For About A Week, I Have Had A Dull Pain

For about a week, I have had a dull pain in my lower right side (in line with my belly button & about 5 inches to my right). It sometimes itches, but I only really feel it just after eating or drinking coffee. The pain is less when I am lying on my back. I also am quite pain free when I work out at the gym (even when doing heavy leg press)