I have lumps on my sterum. I'm a 31 yrs old african american I also have upper back pain on my leftside going down to arm.the pain in my back hurts the worst. I wanted to know if this could be a cyst that has maybe grown and is pushing on a nerve they may be causing the back pain. I do not have a pcp at this time but is looking for one in my area. I've had the pain on my sterum for yrs off and on.