Everybody experiences different dreams. At what level they experience them could be different. If you are having troublesome dreams that you can't explain or can't get over, perhaps speaking with a counselor or therapist can help.
Do you mean dreaming of traumatic things? Or the dreams causing trauma? Our dreams are a product of our unconscious. People have night terrors all the time. I do believe that it's possible to relive trauma while sleeping, however I don't think the content is truly new, it's simply from our subconscious. It can affect you currently, however it was already pre-existing.
I believe that dreams can be traumatic. Sometimes our dreams can seem very real and that can be damaging to us, especially if the subjects in our dreams are touchy issues that we have dealt with in life already.
The answer to this question in my opinion would be yes. It is very normal that the dreams that you may experiencing to be traumatic. This could be from a handful of very normal issues, such as something from the past or a recent traumatic experience. These dreams can be very real and scary. It is important that when you have one that you talk to someone.