What Causes Constant Pain Under Breast While Taking Deep Breaths?

Pain under right breast for 2 weeks. Somewhat constant but worse if taking deep breaths or coughing. Sometimes I feel it in my right upper back. Doesn t seem to be muscle, as heat, cold, changing position does not help. Do not notice any foods that make it worse, but have had intermittent pale colored stools in the past week. No gas, nausea. Is somewhat tender to touch ribs in the area under and to side of breast. Hurts on inspiration.