I am a regular smoker of marijuana. I took a toke of marijuana and choked and now my right lung hurts. Could it b a cramp? It's hard for me to breath

Probably muscular. It is rare to have pain coming from the lung itself. Your choking probably strained muscles in your chest wall/ribcage- esp. If the pain is worse with taking a deep breath. You might try an icepack over the sore area, the homeopathic remedy arnica and Ibuprofen or Aspirin to relieve the pain. If the pain worsens or you feel short of breath you should seek medical care.