Likewise, I had symptoms like this before things got really bad, so I too recommend you get this figured out sooner rather than later.

You said you were active. Watch out for walking where your arms swing down. This can put traction on the nerves and brachial plexus and exacerbate things. If you look up "power walking" on the web, you'll see a fairly consistent tip to keep the arms bent. Sometimes they mention that this is to avoid "traction injuries".

You've only mentioned the one doc. I recommend getting in to see a Physical Therapist (PT) to get their opinion. Compared to most doctors, they will more closely study the state of your tissues, posture, muscle tightness, etc.

Likewise I would get in to see a chiropractor for the same reasons.

You're looking for two things from each of these. (1) Information on what they specifically notice about you upon examination. (2) Potential treatments they can provide that can help you.

PTs and chiros come with different education and perspectives (with some overlap) and it can be useful to see both.

Also, if you could share what you find out and what happens, that would be a nice way to contribute back to this group.