Hey there, I'm about your age and have been suffering from general anxiety for about two years. I've also had what you could call very dull aches or burning sensations in my chest area as a symptom of my anxiety. I have an interesting...technique to share to get it to go away over time.
What happens with anxiety and even a normal (if a bit high) level of stress is you usually build up tension in your core/ torso area (which seems to agitate your lungs), and a lot of us don't even realize it. Only about a year and a half into my anxiety did I realize this. Now I'm no expert, but what seems to be happening is the tension is causing either minor stomach issues which create a kind of acid reflux symptom, or maybe internal organs in your chest area (such as your lungs) become slightly agitated due to the tension- either way, its nothing to worry about, even those who don't suffer from anxiety like we do get these symptoms from time to time when life is stressful, they just don't pay as much attention to them.
Anyway, here's the interesting part, you can let go of this tension. It takes a little courage, but a big part of overcoming the anxiety and the tension you're feeling is surrendering yourself. Now, the easier part is surrendering yourself physically, the more advanced technique is emotionally, but the first is a good start.
So what you do is you stand up straight- you're feeling a slight agitation in your chest like a little itch you can't scratch, now slowly let go of any tension you feel in your torso. What you'll probably notice if you're holding a lot of stress is your heart starts to beat a little faster and harder, which is a good thing, just imagine your body is letting all that stress out of the stressed wells in your torso (which seems to actually be whats happening). When I do this, I feel very bloated in my belly, especially if I ate while I had stress, but by letting go whatever gas/bloating built up, the symptom eventually goes away. Since its a little uncomfortable to stand up straight and do this, I recommend mixing it with a stretch (yoga) position that also helps let go of the tension. An easy stretch to do is to stand up straight, then spread your legs apart slightly (you can bend your knees), then bend over and put your hands on the floor.
So alternate the pose with standing up straight and letting go of the tension in your torso- don't worry if the agitation doesn't go away immediately- remember, you've been building up this stress for a while, it's going to take a few minutes to let go of all of it.
If you want to prevent this from happening, tune in to the way your breathing every once in a while. If you're stressed your probably kind of sucking in your stomach instead of letting the torso push out and naturally rise in and out fully. This seems to be what causes that tension build up