The reason why the upper traps get tight is because they are weak and thus should be an integral part of the strength training regime rather than just loosening them up! The upper traps get a lot of blame and are often loosened, massaged, treated with dry needling and whatnot during physical therapy treatments, while the middle and lower traps get a lot of attention during training because they are often weak. 

Most, if not all of the painful upper traps we see are weak and long, not tight and short, and yes they can "feel" tight and tense, but they "feel" that way because they are overloaded due to their weakness. That is why we should not stretch or massage these muscles, we should do strengthening exercises, which is completely foreign to some.