Thickening Under Arm

I've had a thickening under my right arm for about four or five months. I believe it's a swollen lymph node that just won't go away. I thought at first it was an ingrown hair or a result of using Drysol (which I have since stopped using), but it won't go away. It's painless and lumpy. I have an ultrasound tomorrow of my axilla, but what could be the cause of this swelling?

[zouzi]

Hi,
When a lymph node in the axilla area becomes swollen,it should always be evaluated.The swelling could be due to a host of possible causes ranging from minor injuries, to infections or something more serious.When there is an infection or inflammation somewhere in the body, a lymph node may enlarge and could remain enlarged for a very long period of time,even after the infection is gone.
After your Ultrasound test procedure,and depending of course on what your doctor deems appropriate, he/she may recommend additional tests that can narrow down the possibilities.These tests may include a mammogram,a MRI or even a biopsy procedure if needed.
I hope that there is really nothing serious at all and that no further tests will be needed, aside the Ultrasound.
Best wishes ...