hmmm well if its stickin from weed tryin getting some rubbing alcohol in the bong and try from the outside too if u can
rubbing alcohol shouldnt hurt it, it evaporates if left alone for a l il while and you could just rince it out let it dry and u prob wont have a problem

if its not res makin it sticky idk if lubing it would help any

if u put it in the freezer the glass probly expanded and u shud prob just warm it with a hair dryer or somthing and try again