Lymph nodes in breast

Just over a month ago, I started having pain on the outer side of one of my breasts. I passed it off as torn tissue from all the heavy lifting(furniture). After a month, the point tenderness is still there, although not as big a circumference. I went for a chest xray followed by a mammogram. The mammogram showed a 'cyst', so I was sent for a ultrasound to make sure. The radiologist stated that they couldn't see the 'cyst' on the u/s, therefore it's only a lymphnode-nothing to worry about. Question #1: Why would it show on a mammogram and not an u/s? #2: I have had no signs of infection, what does it mean to have painful nodes, specifically in the breast? I do have family members with history of thyroid, and non-hodgekins lymphoma. I'm 38 and post menopause.

[japdip]

Cysts usually show up on Ultrasound so I'm not sure why the Radiologist has determined that what the Mammogram revealed as a cyst is now determined to be a lymph node. I would wonder if the same Radiologist read both sets of films. I think it might help clarify the situation to have your films read by another Radiologist ... a second opinion of sorts. Either way both findings would not be of major concern.   Regards ....