What Causes Heartburn And Severe Muscle Pain In Upper Back?

I have had heartburn daily and severe muscle pain in upper back, arms and neck for 14 years. I have had previous left sided abdomen pain but this has cleared. My arterial bloods once taken, tested high for lactic acid and I get black marks on my body when I wear gold jewellery. ..im thinking I may have an acid imbalance. ..is this possible? ESR was 2 ...All other tests for rheumatology were negative. MCVs are slightly high. I also suffer with fatigue and constant infections including herpes of the eye and have contracted systemic pseudonomas.