Lump under my armpit

I'm a 16 year old male, and i've had a lump under my armpit for about a month now, and i was wondering if anyone could give me any insight as to what it is.

It isn't very big, it doesn't hurt, although it can get a bit tender if i mess with it, it's pretty hard, and seems to be under the skin. I read somewhere that using an antiperspirant can cause bumps like this, and i use Mitchum Unscented roll on. Does anyone know if this has any type of connection?

[gymdandee]

I do know that Mitchum is a strong antiperspirant I can't use it as it irritates. Don't use it for a week or two and see what happens! If you still have a lump then see your doctor  

[AnnieBrooke]

It could be a blocked salivary gland, one time my husband had this and when the doctor lanced it with a little scalpel, out came all this really stinky sweat.  You might try a hot cloth soak (keep the cloths hot and on the spot continuously for a while) to see if it opens.

[AnnieBrooke]

Excuse me, a blocked SWEAT gland, not salivary.  I believe I was thinking of something my dog had one time in her neck when I wrote that word!  But my husband's problem was definitely a blocked sweat gland.