Could post traumatic stress disorder be related to phobias?

No: Post traumatic stress disorder is a maladaptive reaction to a prior traumatic experience. It has nothing to do with phobias.

PTSD: Phobic avoidance can be a symptom, along with flashbacks and anxiety.

PTSD: I had to think about this before i answered. Although post traumatic stress disorder & phobias are 2 different anxiety disorders there is a possible connection. If someone has a severe phobia, a significant exposure to the dreaded object (enough to cause horror or intense fear) may be enough to trigger a post traumatic response. It may or may not rise to the level of meeting DX criteria.