Lump Under Arm: Causes, Symptoms & When to See a Doctor

Question
I've been sick for a couple weeks with a sinus infection and I recently found a lump under my arm. It had a head so I wasn't concerned, I figure it is just a boil.  I haven't been able to squeeze anything out of it for about a week now.  It is really hard but I still believe it is a boil.  Could I be wrong?  If it did squeeze out a little to begin with, then I shouldn't be concerned, right?  Any input would be really helpful.  I don't have a family doctor right now, but I was just at Urgent Care for this sinus infection.  

Answer
Dear Valerie,   Do "NOT" squeeze this no matter what it is...  That would only set you up for more possible infection...

Since you do not have a family doctor, get yourself BACK to the Urgent Care center and have a doctor look at, determine what it is and if necessary it may have to be lanced...  DO NOT SQUEEZE.......

thank you,   karen