In fall of 2012 I attended a 4.5 month school on Active Duty for Training orders. During combatives training I injured my lower back. It wasn't a situation where I had to go to the ER right away, but I had considerable lower back pain and sciatica pain. I went to the TMC for my back and also for an unrelated prescription refill. I was given the typical ibuprofen and rest with a temporary profile (I cannot find a copy of this profile) and told to return in a few weeks if the pain didn't get better. I returned to the ER several weeks later as the pain had increased and was given different pain meds and another profile. I have a record of my ER visit, but not of the profile. I did not take two APFTs while in training due to the lower back injury. Upon returning home I went to my civilian doctor and was diagnosed with lumbago in early 2013. I was told by my unit that I did not need an LOD because I was on Active Duty when I was injured. Fast forward to 2017 and although I was able to recover enough to pass APFTs between 2014-2016, my lower left back continued to get hurt and has been getting worse. I worked with my civilian doctor and did a round of physical therapy and was starting another round of physical therapy when I got the letter about the intent to medically separate. The letter indicated it was non duty related. I brought in the documents I had from the TMC and ER but the comments on the paperwork were limited and the Medical Services Branch for my state has said that NGB doesn't do LODs for back pain. They need a more specific diagnosis and maybe then they could work the service connection. They also suggested imaging (x-rays, MRI). I discussed imaging with my doctor and he is against it. He also said he can't give me a more specific diagnosis than SI joint/lower back pain. I have two classmates that remember me having a profile and back pain, but it's been so long they don't remember a ton of details. Is there any way I can prove the service connection for the PEB or should I just get out and put in for VA disability? Is it worth going to a Non Duty Related PEB? Should I keep trying to get the LOD? I feel like I'm just going in circles with the Medical Services Branch and my civilian doctors for the LOD.