Hi there, I had a similiar thing with my daughter, she always cried when her head went through the hole of a t shirt or I pushed her arms through her sleeves. I read a lot of articles from the hand in hand parenting website, and one thing I read really struck me. The writer, Patty Wipfler, explained that putting on clothes can be a trigger reminding a baby of the constriction they felt when being born. I've just had a look for the exact article, but I couldn't find it, but i did find this one, Helping Children Through Fears which explains how to help when a child is using an everyday situation to express fear about what happened in the past.
basically in a nutshell, what I did with my daughter was to move very slowly to putting on the clothes to gently take one arm, and then another, if she cried I would stop what I was doing, I woud hold her, reassure her, look into her eyes, tell her she was safe, and then slowly move to continue, she would start to cry and then after getting all her tears out, (basically crying releases stress hormones in the tear, so she is literally ridding herself of all the fear from an earlier time in her life)
anyway after all the crying stopped she let me put on her clothes, and she rarely cries anymore when I do it. If she does cry, it's a sign she's feeling a bit stressed or tired, and I simply repeat the process and she relaxes.
I have repeated the same process with other things by daughter didn't like such as lying on her back to get a nappy changed, (I would gently put her back, and reassure her as she cried, till now she always lies on her back to get her nappy changed),
having her mouth washed after eating, she hated that, and teeth cleaning, which she now loves!!
Hand in Hand Parenting is AMAZING by the way, they teach a parenting approach which explains that our children are naturally 'good' and co-operative, they want to work with us not against us! but when they have experienced scary or stressfull or difficult times in their lives, their emotions go off track, and they behave in a non-co-operative way,
there is also info on the website about playing games to elicit laughter, laughter is another way, fear and tension is released from the body,
hope that helps.