Lower back lumps

I am just wondering if any else has this problem… Below my hips and above my hips I have these two firms lumps one on each side of the spine that do not move. They are round and feel about 2cm in diameter. They are most noticeable when I stand up, and you have to apply a decent amount of pressure to feel them. If you press hard, they are a little tender. They have been there for at least a year (could have been longer but never noticed before) and they seem to be the same size. I am a 23 year old male with no history of back problems. A couple of doctors said its just tense back muscle, but they never really pressed hard enough to feel them. They are almost as hard as bone and quite smooth. I have occasional low back painAnyone else have these lumps? I am thinking of seeing yet another doctor