Hang there. Each day it will get better. Did you have a bowel resection? I had my tumor removed transanally but then had an ileostomy and the reversal.
Be sure to be up walking around, and not just for a few minutes but at least 15 minutes at a time. When you cough, hold a pillow to your abdomen to give it support. Walking holding the pillow may help as well. If you don't have one, get an incentive spirometer. It helps you take deep breaths that will also help reduce the coughing.
Everyone takes different times to heal. As far as the pain, once cleared by your doctor, NSAIDs (Motrin) type medications are better than Tylenol products because the help decrease inflammation as well. NSAIDs can thin your blood so they are not recommended right after surgery. Take your pain medication around the clock instead of waiting for the pain to get bad until your pain is better under control. If you are still uncomfortable, speak with your doctor about changing your pain medications.
I had my ileostomy reversed about 6 weeks ago and my incision is still healing. It gets better and better every day but it does take some time. Hang in there and don't be afraid to call your surgeon.