I have had a spot on my chest for some time 

i squeezed it a while ago releasing dense pus-like goo stuff

(i have had similar 'cysts' or spots or whatever before) But this one had appeared to grow back

i finally popped it again and, along with some pus, some clear fluid and a droplet of blood, a small hard 'stone' came out

it is around 2mm big and is a kind of off white-yellow

worryingly i can still feel what i had assumed to be a cyst sac under the spot but it is relatively hard and will not go away

i am clueless with no help from online research and am beginning to consider a trip to the doctors? Any response at all will be much appreciated,

thanks, 18 year old male