At Night, During The Nigh I Get Pain In Left Shin Bone, Like There Is A Steel Rod In There Push Up And Down. What Could Cause This?

Intermittently, day & night, I also have sharp shooting pains along my shinbones and along the bones of my arms. It is primarily when area is rubbed - such as when I dry off with a towel after my bath - or when I slide my leg on sheet at night. I can't find a doctor who can pinpoint this - one says it is arthritis (I have RA & osteo) and another says it may be pressure on nerves along the spine, radiating to the extremities????