Hi. I have a small lump on my right collar bone that showed up suddenly. It doesn't hurt at all. It's where the two bones come together. I had a scan so I know it's not cancer or injury. Possible arthritis? Maybe I've just used my right arm and shoulder too much. My family DO says it's more common in women. Anyone else have this and know what can be done? It's not ugly but I fear it will get bigger as I get older.