Is MRI/spinal Tap Required To Test For MS After Being Diagnosed With Lupus ?

Hello! My question is about myself. I am currently diagnosed with lupus, but my rheumatologist wants me to see a neurologist to be tested for MS. I cannot afford to at the moment due to no health insurance, but my symptoms are getting worse. Does a doctor have to do an MRI/spinal tap to test for MS or can it be diagnosed without those tests? I am having weakness in my right arm and leg, tingling in my hands, frequent bladder infections and problems emptying bladder completely, have been falling more (in fact think I bruised my ribs), in the mornings, I have noticed that I have trouble with keeping my right arm on task (almost like trying to put the wrong ends of magnets together). I am 42 years old and have a history in nursing, but have had to let that go due to my lupus, so I am currently in a sedentary job, but that doesn't help the fatigue and weakness. Anything I can do or do you think this is related to my lupus?