Noticed Movable Lump Under Collarbone. What Could Be This?

Question: I am a 26 year old male. Last night, I'm not sure if I was scratching or pushing on a muscle or what, but I discovered a small, approx. .5cm moveable lump under my left collarbone, in the area where my pectoral muscle meets the collarbone, about 3-4inches from where my shoulder starts. This lump is not visible to the eye, it is only 'known' to be there if you put slight pressure on it, and it 'slides' over on top of the collar bone. When released, it returns to its normal position. This lump is not rock hard, but it is not 'squishy', and like I stated is moveable.

My friends wife is a nurse and she looked at it but said I shouldn't be worried because it is probably just a lymph node and is moveable and not worry unless it gets larger. She said if I wasn't able to move it, then I should get it looked at. Of course since finding this I have been looking up all kinds of stuff online and getting worried from some of the responses....which is definitely the wrong thing to do. I have no other symptoms of anything, I got over a cough/allergy cold about 2 weeks ago but currently feel just fine. The 'main' lymph nodes in my neck/throat area are not inflamed.

I have recently lost my job and have no health insurance and have not yet signed up for COBRA, so I am hesitant to do anything because I feel I am probably getting worked up over nothing.

This is not a picture of me, but I want to pinpoint the location for you all. See where this guy has the 'dips' below his collarbone on both sides? I think that's called the triangle area, the bump is there on my left side. You cannot see any type of bulge or anything, but when you put pressure on it, it moves up over the collarbone and then you can feel it.
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