<s>[INST] im 37 yr 165 lbs male i have a small lump on my lower back on the left hip side. It is not paining much, but once in a while I feel small pinch. This small lump was there for almost 3 years. I remember I was playing Tennis in hot sun in Arizona one day and was dehydrated and got this lump the next day and it stayed there. Was this lump due to the muscle spasm or anything else is I am worried of. Please let me know. Thank you very much. [/INST] Hello and welcome to Chat Doctor, A lump on lower back on left hip region is most probably due to soft tissue swelling. Muscle spasm is unlikely to cause a lump or swelling. Imaging of the lower back will help to determine the relationship of the swelling with the bony structure. Imaging can be followed by aspiration cytology of the swelling. In aspiration cells are aspirated, spread on a slide, stained with appropriate stains and studied microscopically. This investigation will determine the origin and nature of the swelling. Management of the lesion can be done after this investigation. Consult your primary healthcare provider for clinical assessment, investigations and thus management. Thanks and take care Chat Doctor.  </s>