Hi there,
Im a 21 year old male and I have a few symptoms that I can't get out of my head

I have a small lump in my left breast and have had it for about 3 years. It hasn't gotten any bigger and I've had an ultrasound done on it that came back showing it to be non-cancerous.
I also have an enlarged lymph node in my neck/throat just below my jaw line, only on the right side that sometimes swells up and sometimes is normal, but I've had this too for about 3 years.
In about the past year I've developed a pain in my right shoulder, 99% of the things that I do in my everyday life don't effect it at all. But I can feel like it's slightly swollen/enlarged compared to my left shoulder. When I raise my right arm above my head like I'm pointing to the sky and bring it back down slowly and to the side my shoulder cracks, every single time that I do that motion.
Recently, in about the past month I've started to get a tightness in my chest, almost exclusively associated to the days after I consume alcohol but not only on those days. I'm constantly thinking about these symptoms and second-guessing the ultrasound results. Cancer is in the forefront of my mind whenever I start thinking about all these symptoms and my chest tends to feel like it's tightening when I think about them as well.