I have a hard bulge or lump in the lower section of my left leg under the skin on the fibula bone. I noticed this several weeks ago and dismissed it at first bc It is not painful to the touch and it does not move. No bruising or discoloration ....However, my left leg has been aching a lot throughout the day . .. it gets pretty painful especially at night. ..even though the bulge does not protrude through the skin, it's very noticeable when I run my hand up my leg...as I stated before. .it's not soft and does not move. To make sure this isn't something that's supposed to be there I felt my right leg in the same place as the left and I feel a slight difference under the skin but not nearly as big as on the left and the right leg has not been aching as bad as the left...it's totally different. What could this be? Should I be concerned?