Was there a history of injury or trauma to your back? Can you elaborate on the rashes on your stomach? What other symptoms are present? The rashes could be due to a variety of issues such as irritation,allergic reaction, infection as well as skin conditions such as dermatitis. Rashes associated with pain may be caused by viral infection like shingles and may warrant further evaluation by your doctor for direct clinical examination. The back pain may be musculoskeletal, neurological or associated with the rash. Take care and do keep us posted.