I get a strange feeling in my chest when i smoke marijuana.. it doesn't always happen. i smoke marijuana maybe once a day. is this just panic attacks?

Not sure: But you have to wonder, what do you get from smoking marijuana that is worth this experience?

Heart / lung effect: Short-term effect more likely cardiac arrhythmia. My take on the research available is that mj smoking probably does have adverse chronic lung effects. Short-term effect on lungs is less clear. Also, unless you produced marijuana yourself, it may not be pure mj and could have been adulterated with other drugs. I have seen quite a few cases in er where urine testing came back with more than mj.

Maybe: Maybe your body is telling you something -- like your lungs don't like being choked with smoke. I agree with dr. Ho also, that your marijuana could be adulterated with additional substances. You wouldn't know unless you had it tested -- or you land in the emergency room where you end up being tested (along with your urine). I hope you listen to those signs from your chest and lungs.

Many effects: Weed has many effects when smoked, including changes in cardiac function, brochopulmonary changes, cardiovascular effects. Any combination of these plus weed's propensity to trigger anxiety or panic can be causative in your symptptoms.