Joint and muscle pain

In June I was hospitalized for seven days with an unknown illness. I was having trouble walking due to severe pain in the large muscle of my left leg. While in the hospital, my right knee started swelling and was drained. I had every test one can imagine. Saw many specialists to include Infectious Disease. When dismissed, the diagnosis was inflammatory arthritis and advised to see a Rheumatologist. I was given heavy doses of steroids which seemed to clear up the pain somewhat. I was on a walker for a couple of weeks after returning home and then a cane. During this time, I continued to have issues with my right knee and still do. I attempted to try to reclaim my life as it had been before this occured. I have had joint pain as well as muscle pain every day of my life since being released and getting off the steroids. There is not a day pass that I have pain and have trouble lifting my arms above my head.
The test run by the Rheumatologist came back negative for any of the diseases associated with inflammatory arthritis.
I am a 79 year old female who had been active in an exercise program at least four days a week. This episode occured shortly after I learned that my husband was diagnosed with IPF. I had also had my 96 year old mother with me which I was caring for.
I would like to get back to a normal state and do not know what to do next. I did test positive for autoimmune disease but not sure what kind as the test that were run for some of the various diseases under the autoimmune diseases, came back negative. Just wondered if anyone on the Mayo Connect hhad ever experienced anything of this nature. I am now trying cannabis to see if this helps with the pain. Thanks in advance.