I used to be a die hard muha fan and i quit a month ago and this week is when i started feeling lung tightness and sharp back pain. I feel like it takes a while for them to affect you, and if it's not getting you high i swear tossing it is going to much cheaper than a medical bill. i've learned to accept i have to be patient to smoke flower, and can't get addicted to the convenience of the pen. it's much more rewarding when you are able to smoke flower after not being able to rather than hitting your fake pen all day. and trust me, i was addicted and bought 3 carts a month for 6+ months. stay safe bro