I doubt there is just one "underlying issue". Mechanical imbalances can also lead to tension and blood flow problems that further aggravate already bad mechanics. A muscle in spasm and wound up tendon will make any mechanics worse. So bringing in blood flow and resetting the Golgi tendons though such energetic therapies such as light, microcurrent or ultra sound will definitely help to correct part of a syndrome at best or bring healthy blood flow to the area at worst.
On the other hand, Tendon inflammation is a sign of overuse. there are a few difference categories of "overuse".
1. Tendon is healthy (in a healthy, non chronically degenerative environment)
In this case then yes, either mechanical problems or overtraining are likely to blame. Rest, PT, and posture corrective training will remedy the "itis"
2. Tendon is unhealthy.
In an unhealthy tendon situation there is a mix of cellular/ECM imbalance, Chronic inflammation/or progress to non-inflammatory tendinosis, and also chronic MMP degeneration.
IF the tendon is unhealthy due to the second category, then degeneration and damage must be stopped by reducing/balancing MMPs and reducing oxidative cellular damage.
In almost every case Infra-red light therapy should help. Even in hyper-cellular non-inflammatory tendonosis, the increase fibroblast stimulation and collagen production from light should help to rebalance the ECM/cellular environment.
So, any therapy that helps to stimulate healing process, increase blood flow, and lower inflation, will most likely be helpful.