You've obviously been playing for a long time with some heavy old basses strapped onto your body. Any experience with chiropractors helping discomfort? I always feel the best in general when I'm eating right and staying hydrated and happy, but I definitely have some neck crackles and pops that persist further sometimes. Bad posture sitting in a chair at the studio desk or standing with a 15lb hunk of wood on a strip of nylon webbing around my neck might be contributing!!