Going to try and make a long story short. I have a 10-year-old quarter horse gelding who I have not ran barrels with in nearly 3 years. I kind of just lost the love of barrel racing, I didn't retire him from barrels due to any other reason. April 20 23, his left front tendon flared up, and it was a mild case of tendinitis. Got an ultrasound done, stall rest, hanwalking,magnawave, wrapping, icing, it healed. Brought him extremely slowly back into work, and within a couple weeks it was swollen again. Now, three weeks ago, it flared up again for the third time. All has been in the SDFT area.

i board at a barn, unfortunately, with really bad footing in both the indoor and the outdoor. I am working with a performance horse vet, and we are kind of trying to narrow down why this keeps happening, and we are chalking it up to really deep and uneven footing. His confirmation is good and he's not overweight.

even though he has another mild case right now, I'm sending him out for rehab for two months. I guess I just feel really bad for him, a life of hand walking for 10 minutes is not fair to him. He loves to be in work, he has literally nothing else wrong with him. Our farrier is the best of the best, and I do x-rays very frequently to make sure everything is good. And my farrier is taking the toe back to help, nothing to change in the shoeing. Angles are great, etc.

With his current tendinitis and his other two bouts, he never went lame, just swelling.

we are looking at another barn potentially after he's finished rehab.

i guess I'm just sad for him and scared he's never going to live his life to the fullest like he used to. I'm afraid it's going to keep flaring up.

my future goals with him is for him to be able to run around in the pasture again and ride/lunge him 

I highly suggest manual body work. My personal favorite is a 'structural integration' practitioner. They will be able to address any imbalances in the body that you don't necessarily see visually or on X-ray which can greatly impact how they are using their body. 
We don't have an osteopath in our area but if you do, I would absolutely seek them out. 
IME tendonitis is a symptom of an imbalance/issue somewhere else causing overuse  of the tendon. Also important to make sure your feed program is balanced and providing adequate copper, zinc, manganese as a base. If you're in a high iron area, your feed is probably lacking in those minerals.