question: I have a lump to the back of my L shoulder about the size of a golf ball.  I have had this for about 1 month and have been off work due to the pain.  I am going for physio and the Ultrasound and x-rays are normal.  I can see and feel this lump and so can my doctor.  He is treating it for bursitis but could this be a tumour of some kind?  Would I need further testing to determine this by MRI or bone scan?