Nagging lower back issue.

Hey everybody, I am 21 years old and fractured my L1 vertebrae while snowboarding about two and a half years ago. I was in a back brace for about two months and recovered fully. I did not take physiotherapy as seriously as I should have and I am now paying for it.
I have recently become very active. Three months ago I began training in Mixed Martial Arts and working out in the gym regularly. I have become much stronger and feel amazing.
I became aware that my back is still an issue after playing softball a few days ago. The motion of swinging the bat really bothered my back. It worsened later that day to the point where I would have trouble bending over to pick things up.
Any information you guys could give me in regards to specific muscles that may be giving me problems or even exercises to strengthen my back would be greatly appreciated.
Also, what are your thoughts on yoga as an effective way to strengthen core muscles?
Thank you in advance.

It would probably be best to see a physiotherapist for accurate diagnosis of the cause of your symptoms and appropriate treatment. In addition the physiotherapist should be able to identify any contributing factors such as poor flexibility, poor core / pelvis stability etc. that may have contributed to the development of your symptoms. These factors would need to be addressed with specific exercises to reduce the likelihood of symptoms recurrence.

Hope that helps and good luck,
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