Yes but chiropractor for sure! Even not pregnant, you shouldn't be cracking your own back with pulling or straining moves
And I was like 36 weeks at the time.
I just had mine popped a couple weeks ago by my OMT.
Yes, but it would be safest to find a chiropractor skilled in pregnancy related issues. Some don't treat pregnant women, especially as ligaments are so much looser. They may also decide 'popping' your back is not the right thing and treat you with other methods instead. Osteopaths can be very helpful too...