Stan's the man about the chakra information. I would suggest making sure you don't eat anything during the few hours before going to bed, and if that doesn't help, maybe avoid anything really spicy altogether. Do you drink tea? Some type of soothing green tea with honey (no caffeine) is nice before bed. Valerian, lemon balm, chamomile, jasmine and peppermint are some good ones. Yin yoga and meditation help me sleep better, too. Sometimes we just have toxic dreams that don't really mean anything when we don't sleep well for whatever reason.
Regular physical issues aside, that leaves you with the facing that there is something in your world or history that is still upsetting you. You can figure out what it is with a little work...again meditation (along with good diet and exercise) is the best way to get to the bottom of deeply rooted emotional issues. Sometimes we just don't want to see things, tho.
I used to have a recurring nightmare over decades. I didn't figure out what it was until many years. I think it had to do with me being on the wrong road in life, but I was at a total loss to see it for so long...until the thing was over..lt was something I couldn't/wouldn't face.