Microscopic polyangiitis - Any help would be greatly appreciated

I have been dealing with a mystery health issue for now 2 years, it all started after working out, my pectoral muscles cramped up on me two weeks later the fasciculations started all over my body, then horrible mid back pain, under my arms and pecs, then a month later horrible pain on my hamstrings and legs.
After 8 MRIs, 4 EMGs, and Tone of blood work, 3 Neurologist, 6 Ortho surgeons, 1 Neuro surgeon, 3 rheumatologists, also including diagnoses such as Bening Fasciculation Syndrome, Cramp Fasiculaiation Syndrome, Probability of Stiff PErson Syndrome, probability of ALS, I had my new rheumatologist and he ran about 50 blood test to which the followings came up positive and pointed to the diagnosis of Microscopic polyangiitis. ANA SCREEN, IFA POS, ANATITER 1.40, ANCA SCREEN POS, and ATYPICAL P ANCAT TITER 1.320
Got prescribed Azathioprine but am still in a lot of pain, now on my pectoral muscles
I started taking steroid 4 mg on my own because my pain management provided it and it has helped some
I wanted a 2nd opinion and the Dr. instead of taking my case is told me to go to Mayo that scared me a lot more.
I'm the only breadwinner at home and I'm not liking what is going on and don't see the light at the end of the tunnel, not sure what to do, as all these test and treatments are very expensive and don't want to give up, even though some times, is just rough to come out of bed.
Thanks