This is something i have had a lot to do with as i suffered for a long time with severe OCD.
It is a hard battle and something that’s probably best helped with therapy and some sort of programme to tackle it head on.

OCD is a coping method and an anxiety disorder which is a good thing to remember. It is a good idea to look at what you do and see if you’re doing these things more when you feel anxious.
Obsessions are thoughts that you cant get rid of just by ‘not thinking them’ so it is a tricky one. In the past i have set myself goals for example, I would only check the door at night 5 times and then make myself go to bed. Sometimes it was too hard and i ended up continuing anyway but its worth a try that way.

Maybe try writing down all the things you check or do and make an anxiety ladder. Starting with step 1 on your ladder the least difficult. Try and work out how many times you check/do that thing and try and do the minimum or try and do it one less time each day or each time you do it. Once you have tackled that or feel like you’re getting somewhere move on to the next step.
Maybe even treat yourself to something nice when you reach your goals!

Remember ocd is anxiety based so you could need a little help for anxiety.

Gosh,this is a tricky one isnt it?

Post traumatic stress disorder is caused by traumatic or stressful events so i don’t see why not? but maybe the reason you self harm could be what triggered off the ptsd?

I think if a certain place/person/object reminds you of something traumatic it can always be well, traumatic.I remember when i wouldn’t go back to my home town because the whole place made me feel uneasy.I think its only a natural reaction.