lump in armpit

I sometimes get a lump in my armpit, but it goes away after a few days and then it could be months until I have another one.It is in the upper part of my armpit and sometimes the area will even be red around the area. I do feel some soreness around the area sometimes, but not all the time. I've read that sometimes a lump in the armpit  can have something to do with breast cancer. I was never too concerned about it until a friend of mine found a lump in her breast and I read up on breast cancer. Should I be concerned about this? I haven't had one in maybe three months, but the last one didn't bother me and I only  noticed it because I put my deodorant on in the mirror. What should I do?

[CCF-RN,MSN-rf]

Dear remor518:  A lump that comes and goes is not generally cancer-related.  If it is also red and sore, it sounds more like an ingrown hair or pimple.  If a lump stays more than a few weeks, gets larger and doesn't go away, you should see your doctor for an examination.

[surgeon]

something that comes and goes is almost certainly not cancer. It's not rare to have recurring infections in sweat glands under the arm, and since you see redness that makes it fairly likely. It might need surgical drainage to make it go away permanently. Also, using deodorants that don't have antiperspirants, which plug up the glands, can be useful. But to have it accurately diagnosed, it'll need to be looked at by your doctor.