Any doctors or nurses? What causes phlegm and pressure in chest?

I feel a bit of a rumble/crackle in my chest sometimes along with phlegm in my throat too. The pressure in my chest isn't terrible and I work out just fine and feel great other wise. The pressure comes and goes. Could it be allergies or most likely something else? I realize it could be a number of things, but I just moved so I'm going to call around today to see who takes my insurance and find a new provider. Unfortunately, it may be a while until I can be seen as a new patient. Going to an urgent care is out of question since I'd have to take two kids with me. I was just wondering if anyone else experienced these symptoms and what the issue was. Or, if there are any doctors or nurses on here that can give some advice, it would be very much appreciated. I've never experienced anything like this chest congestion before and it's been going on for about a week now. Thank you in advance! ❤

I'd also like to add, I don't have a cough nor do I smoke.