Is this something serious?

[ManthonyW]

Over the past couple weeks, whenever I rest for an extended period of time, upon standing up and moving around I can feel a clicking in my back, specifically when going up an incline like stairs. Today I felt this More than usual, so I started to stretch when I got home from work. Shortly after stretching, multiple contusions(that's what they appear to be, one of them looks like a regular bruise on the bottom part of my spine, and three of them are bloodish red on the back of my left side, just behind the lung). They don't seem to be growing in size, but my back burns immensely and I can't sit down without it hurting. I can almost feel the bruises, like there's a fluid or blood under the skin. My heart rate when I just tested it was 81 bpm, and I can breathe mostly fine, though my anxiety is starting to get to me. Any input(but a professional input would be much appreciated)would be great, and if I need to go to a hospital, that would be great to know right now as well. I'm 22 years old and I have the following problems ongoing at the moment;

Possible Carpal Tunnel
Gastritis
Taking Omeprazole

I'm a pro gamer(hence the Carpal Tunnel), and sit down a LOT. I don't feel overly fatigued. This only started maybe like a month ago, after I was diagnosed with Acute Gastritis(but I was diagnosed at an Urgent Care center, with no tests or anything being done to confirm, so possible misdiagnosis?), and was bedridden for a little bit. My chest also makes this weird squishing sound and you can hear bones cracking(but it isn't painful)when I lift my shoulders up and drop them real quickly, but this only does this very occasionally. My throat is tight, with possibly swollen lymph nodes under my chin and you can see my heartbeat in both my neck and just below my chest cavity, but my blood pressure comes out normal and so does my BPM.

I have no clue what is going on, and it's starting to scare me. Living in NH, the doctors around here(except for Dartmouth)really don't give a **** unless it's your PCP. Anybody who can give me a hint of what's going on, or a doctor who thinks I need to go to the hospital would be greatly appreciated. At 22yo, the Urgent Care center nearby kind of just dismisses me but I feel like there's something a little more serious going on but I don't have a PCP so I don't want to go the Emergency room unless I absolutely have to.

Thank you in advance. Hopefully some of what you say can help ease my anxiety. I've been completely healthy my entire life's until Gastritis appeared, and then everything else started happening.

Help :(