The long head of the triceps is a really overlooked structure in the development of both shoulder and elbow pain in throwers. Many people forget that it crosses the shoulder joint - and therefore effectively links the scapula to the lower arm.
In the late cocking phase of throwing, it's working eccentrically to prevent excessive elbow flexion while storing elastic energy that can be released on the subsequent elbow extension of the delivery. In other words, you can view the long head of the triceps as somewhat of a "mini-lat;" the lat serves this similar store-release function (albeit with different functions) - and they both work as shoulder extensors.
It's also interesting in that it's one of the few muscles where the trigger point referral patterns can work up and down, as opposed to just down. I've seen some throwers where treating triceps has been a game changer in terms of everything from elbow, to shoulder, to neck, to diffuse nerve pain.
The long story short is that you have to give the triceps some love with quality self-myofascial release/manual therapy and make sure that you preserve tissue length (by stretching into shoulder flexion and elbow flexion simultaneously). See below for some ideas.🧵👇