Pain In Lower Right Side. Went To Dr And Check

Pain in lower right side. Went to dr and check for hernia about 1.5 years ago. No hernia and went away by itself for a while. Told me it was muscular. Back again for about 3 months. Feels like the pain is worse but still a dull, achy pain. I can feel it when I am lying in bed, exercising like holding a plank, or pushing a bar over my head.