Egg sized lump under my left armpit - had for years but it’

Hi folks,

I have had a lump about the size of a small egg under my left arm for a long time. About two years ago I had it scanned - after both a GP and a nurse couldn't feel it. 
 

The scan came back clear and I was told it should just clear up at some point. The thing is it hasn't. I just accepted it as a part of me - lumpy, but me, for the next two years. 
 

It's been worrying me a little more lately, it seems to have grown. It's grown very slowly but it's more obvious now. 
 

I don't know if I'm being daft and they'll tell me off for wasting time today, or if the GP will refer me. I just needed to talk to someone because in the likelihood it is just a lumpy me I don't want to worry anyone and be seen as a drama queen! 
 

I don't have any pain, just tiredness and all the itching a girl could ask for. The lump isn't entirely a hard rock but it's not "spot" squishy either. It's like someone has put a squashy egg in my armpit. 

Sorry for the long post. Fingers crossed they can give me more information this time. 
 

Thanks for any advice in advance.