I have had a pain on the left side of
need to be evaluated by orthopedician / rheumatologist...
Since you been dealing with the pain for a long time, it would be better to understand what is causing the pain. It looks like the pain is arising from the spine. Osteoarthritis is a condition where there is age related degeneration in the spine. It makes spine stiff especially after bed rest and eases as the day progress. Besides osteoarthritis sometimes systemic causes related to low hemoglobin and nutritional deficiency may cause back pain.
Without physical examination, I don't think I will be able to comment more. Hence I will recommend you visit an orthopedician or a rheumatologist. A detailed clinical examination of spine followed by a few test will help identifying the cause of pain. Management will be much easier thereafter.
Until then I will suggest taking calcium supplements and use over the counter pain medications occasionally.
Hope this helps. Let me know if you need clarifications.