Large Painful possible lymph node on collarbone/ neck?

[Meganrose7]

For the past year or so I have always had a small hard nodule at the base of my neck, but you couldn't see it.. I could just feel it. (Probably no bigger than a half a cm) it has been able to move with my skin and has never been painful. Since it never grew it never seemed like I needed to get it checked. 8 days ago I noticed the spot was sore and had grown a little bit, but not much. Over the course of the past week it has grown a LOT and became very red, painful, and warm to the touch. Four days ago I saw a doctor who quickly dismissed the idea of it being a lymph node and said it was probably an infected cyst and gave me a ten day prescription of antibiotics and said to come back if it didn't go away in those ten days. At my appointment she noted the entire lump was "very firm" and was 1.5x2.5cm. I'm currently on day 5 of the antibiotic and it's continuing to grow. It is now 2.5x4cm and is mostly hard but now has a fluid filled part growing directly up off of the top of the lump. Now I also have a couple sore spots on the other side of the base of my neck right at the top of my collar bone (same area just different spot as the lump). There are no lumps that I can feel on the other side, but whenever my neck is touched the areas are very sore. Does this sound like it could be lymph nodes like I had suspected at first or is it normal for a cyst to keep growing while on antibiotics and the sore areas on the same spot but different side of my neck are just coincidences?