It is totally possible to have RA and Sjögrens even through blood work does no show it. You can be zero positive. So many things you described reming me of Sjögrens. Sjögrens has inflamed joints, sores in mouth, eye issues including dryness, infections, and serious issues. Sjögrens causes issues with muscles and tendons along with bursitis. If they said no to Sjögrens did they do a lip biopsy? They should have. I know of an amazing Sjögrens group with informative folks and constant post. If you want it just let me know. Do not let them off the hook. I think they are trying but some flags were raised. Such as them not knowing you can be zero positive and not doing a lip biopsy. Hang in there and keep advocating for yourself.