Cyclical Painful Axillary Lump

I am 41 years old with 3 children.  For my past 4-5 cycles, I have had a painful spot in my left armpit.  It seems to start at about the time that I ovulate, and it gets progressively more painful until the day I get my period.  At that point it seems to go away until I ovulate again.  It seems to coincide with when I have tender breasts.

I was able to see an OB/GYN this morning while it was still inflamed but going down (period started last night).  She said there is a lump in the spot I described, but she could find no other masses on either breast.  I think she said the lump was 1-2 cm at the time.  I am scheduled for a diagnostic mammogram and ultrasound this Friday.  She seemed to think it is something hormonal, but I can't help but worry that it may be more serious.

Has anyone had experience with an armpit lump that painful premenstrually?

[Cleveland Clinic]

Dear meowster:  Having this checked out is the appropriate thing to do.  Without further evaluation it is difficult to say for sure what is causing your symptoms.  

[penelope777]

I am a 46 y/o woman with a painful lump under my left armpit too. I have very deep pain in this area if any one hugs me on my left side or I palpate the area. I have had a mammogram, and they are doing an mri because I do have some swelling of my lymph tissue, any body else experience anything like this?