Pain in upper left side of back relived for brief moment with bowel movement?

Maybe constipated?: Are you constipated? A medical definition is bowel infrequency (less than one bowel movement every 3-4 days). What's "normal" for you? The fact your symptoms abate after decompressing your gut by defecating suggesting a colonic source of distress. Examination is in order certainly for your reassurance & accuracy of diagnosis.