Lump above collar bone

I'm new to this forum, just found it tonight. I have a soft lump above my collar bone about the size of an egg, I've had this for 5 months now. I went to the Dr. she sent me for a chest xray because she felt what she thought was lumps there also but it came back fine. My white blood count was high. She put me on antibiotic, I've been on that for 8 days now but the lump has not changed any. I have no pain at all around lump, I do have pain at back of my neck. Has anyone ever experienced anything like this and if so, what is it. My Mother has Leukemia, I know it's not suppose to be hereditary but this really has me scared. Thyroid and everything else came back fine. I stay tired all the time, some days, I stay in bed from the time my kids leave for school until time for them to come home. Anyone have any answers as to what this might be? Tweet