My understanding from reading about dreams from various sources over the years is that everyone does dream. However, most don't remember their dreams. When you sleep, dreaming is part of a cycle your body runs through. I believe each cycle is about 90 minutes. (There was a study done on this. Where they woke up the subject every time they had a dream. Which gave evidence to the cycle which dreams are a part of.)
If you snore, for instance, you will have difficulty going through the cycles which lead to deep sleep and dreaming since snoring disrupts the air flow while you sleep and thus alerts your brain that something could be wrong and that it needs to address the air flow problems before continuing the sleep cycle.
So, if you have trouble sleeping, you may have difficulty reaching the dreaming stage. I would suggest that you when you go to bed with the intention of dreaming, that you find a position where you are totally comfortable and you create a sleeping schedule (by having a sleep schedule, your body will prepare for the time when you go to sleep, and thus you will have a more effective sleep and are more likely to dream). http://sleepyti.me/ is a great website for setting yourself up for a good sleep since it will tell you when you should go to bed in order to have an effect sleep for when you wake up when you have to or until when you should sleep until if you have a bed time.