I am sorry that you struggle with this challenge. Often the one thing a person struggling with PTSD does desire is being hugged and comforted. However, there are some that really "do" feel uncomfortable with it too. Often this has to do with a person being told that abuse is love which ofcourse it is not the case. Yet, this can create a deep confusion in a person where a hug can be extremely uncomfortable and triggering.

It definitely "is" hard to explain to others that you would rather they not hug you. I think that the only way is to take that person aside and say, I understand you are just being affectionate, but please understand that it makes me uncomfortable. If you know the person well enough you can explain a little more, if not just do your best to keep it simple and do it quietly.

Unfortunately, people do not understand that "any" reminder of a trauma just sends an alert, it's just how we are designed to survive.