Lupus can cause infllammation in your muscles producing weakness and pain.
Have you been tested recently for SED rate or CPK? SED indicates if an inflammatory process is active in your body and CPK is a measure of muscle breakdown. CPK is normally given for different neuro muscular diseases like polymyositis and dermatomyositis. Some patients, like me, have an overlapping connective tissue disease and it often includes lupus. I have MCTD which is lupus, scleroderma and polymyositis.
Is the pain and weakness symmetrical? Thighs only? How about your distal muscles (those away from your trunk)? Any problems raising your arms?
If it continues you should see your doctor but be very specific what muscles and how they are affecting you functionally.
Hope you can get some answers.
MCTD (lupus, scleroderma, polymyositis). Diagnosed 2005. Kidney, liver, GI tract, dysphagia, raynauds, Barretts esophagus, quadriplegic in 2005. Recovered and now active in skiing, tai, chi, hiking, golf. Meds: prednisone 2.5mg, imuran 25mg, amlodipine, benazapril, omeprazole, potassium, folic acid, vitamins, maxide and various supplements and vitamins.
Remain optimistic and you can overcome the odds.