Help me get a good hit

I’m not new to smoking but lately I can’t get a good hit. I put a rock in and melt it a little, hold it up and slowly bring it down but the flame doesn’t seem to be sucking in through the pipe. And after a few hits it becomes oily with gooey resin. I just cleaned my pipe, put in new chore, took a hit, but again I’m not getting smoke through the pipe. It only sucks through for about 15 seconds then I can’t get the flame in anymore. Suggestions. Advice. Videos appreciated