although weed does speed up your heart somewhat, 170bpm resting is somewhat dangerous. especially if you're feeling heart problems the day after. it'd help if you could tell me what your resting heart rate is so i'd have something to go off of. You could just have a naturally fast heart beat, which could be caused by not enough exercise or cardiac arythmia. this is all speculation of course, but i only tell you to try and encourage you to see a doctor if the pain keeps up, or before you plan on smoking again.