For me no touching has come from my fear of being assaulted again, its like waiting for my ex to come through every door & round every corner, even though he no longer lives in the country. I can't tolerate people touching me unless I can prepare myself for it & then its only a brief kiss & I automatically hold their arms to prevent the hugging bit! h My friends are great about it, family find it harder. A colleague grabbing my shoulder at work & causing me to have a flashback & panic attacks was what finally alerted my GP to my PTSD.
My way of dealing with it is to retreat within my clothes, I never have bare arms, shoulders, back or feet when I'm in company although I can do this when I'm alone at home now. I went on holiday recently & it was so great to have the freedom of sitting alone on the cliff tops with bare shoulders.