I have 4a curls that have been at neck length when straightened for over four years
I used to straighten my hair once every 2 weeks but have only straightened it once since November and hav been wearing box braids for the last 3 months.
I don't know about you but prior to me going natural, my hair grew to just past the collar bone (maybe a few inches past and that was pretty much my length. Now that I'm natural, I feel like, that just may be my length because it can't seem to grow much past this. And with the shrinkage, it basically sits at my neck in the back and my eyebrows in the front.
Hey I really don't want to seem like a know-it-all but I was in a similar situation a few years ago so I really want to help, I hope I don't come across as too over-bearing...So, I would recommend trying a different protective style like crochet braids (box braids can be quite heavy for the hair) where you have access to your hair and scalp so you can moisturise. I would say you should try to moisturise with water and an oil daily and also massage your scalp for at least five minutes every day with an oil. To boost hair growth you can try the inversion method or onion juice/cayenne pepper oil. And I think your hair can definitely grow past neck/collar bone length as the shortest possible terminal length unless you have a medical condition is approximately 12 inches so about bra strap length- it just takes consistency. Also deep condition and deep condition and DEEP CONDITION! Hope this helps. xx