What could it be? Chest pressure but no problems breathing.

Hello, 2 days ago I started experiencing soreness on my chest. The next day I went to the ER and got tested for a Heart attack and got a chest xray. I don't seem to have any problems breathing but the pain is quite annoying. Almost feels like I got punched in the chest and have brusing but there's no redness externally. Also the pain seems to move from left side of chest to right side randomly. Right now it's on my left side.

I have smoked marijuana for the past year or so and I stopped since I experienced the pains. It could of been triggered by inhaling too much or perhaps its was too hash.

One doctor said something about a CT scan but this was one day after the chest xray. From my understanding I think they should do more tests before they expose me to the radiation if it was unnecessary. Plus I've had no time to recover
it's day 3 now and pain has went down a bit but is still there.

My question is should I wait a week before doing that, I much prefer not to be exposed to CT scan radiation if I will heal
by myself or with medication.

Also does anyone know what it could be? Me thinks it could be muscle due to not having any breathing issues or pains when breathing in and out.

I'm done smoking and hate the stuff now, this experience has changed me, I just wanna feel better now.

Thanks!