 [ Symptoms ] i am tired legs feel heavy and have disequilibrium doctors can not pinpoint problem [ Disease ] in my opinion none of your symptoms are systematic and they may be multiple system involvement so i think low back or lumbar disc lesion could be a possible cause of your lower limb heaviness and fatigue allergic reaction is possible cause of rash your immunity seems weak and you may be having deficiency of some vitamins and malnutrition balanced diet and stress release and healthy life style can be helpful solitions