Hi all, I started playing (jazz) upright bass over 5 years ago now (after starting BG much earlier), and was, until rather recently, serious enough about it to study in a university jazz program for a few semesters. While I love jazz, playing music with others, etc., I chose to discontinue my jazz studies for the time being, about 8 months ago. The reasons for my decision were various, but the one that bothers me most is my apparent inability to ever get totally comfortable on my chosen instrument. The predominant problem is soreness and exhaustion in the left arm/shoulder/back area. Note that this is not pain I am describing: I dealt with actual pains in my left hand early on in my DB studies but eventually resolved them with the help of teachers. Instead, it is more of a soreness akin to lifting a weight, and usually begins about 15 minutes after starting to play; in cases of playing many hours a time it often becomes a distraction from focusing on the music (and this has been so even in periods of regular practice). I have raised this issue with every teacher I have had, and many other bassists I know/have known. It seems that, when I have gotten a straight answer, the implication is that this discomfort really cannot be resolved through improvements in technique but only through building strength/stamina in the left arm/shoulder/back area. I do have a small, scrawny build and I wonder if this contributes to the problem (although I have met plenty of seemingly unfazed bassists smaller than myself). Perhaps sitting down or a bent endpin would help with this issue? I have experimented with sitting positions but ultimately have found the limited freedom of movement to be a drawback in itself (plus the minor hassle of bringing stools to gigs). My big question is: Will there always be some exertion required from the left arm/shoulder/back area? It seems that simply holding your elbow up to shoulder height would make this so. Again, I have applied all the usual methods for good standing posture and have worked on these with teachers: what remains is this nagging discomfort which I suppose can only be eased through building necessary muscle? I guess I don't want the musical instrument I spend so much time with to feel like lifting work. Any input is greatly appreciated.