My sternum is painful with an egg shaped knot at the base. i had an x-ray and was told nothing looked abnormal. the pain is low grade but constant.

Sternal pain: More history and exam is needed to further make suggestions. Chances are the pain is coming from the muscles around your sternum or a cartilage attached to it. The condition is known as costochondritis. Xrays would be normal in that condition. You warm applications, anti-inflammatory medications such as ibuprofen/naproxen would be appropriate, avoidance of activities known to make it worse.