Hi everyone TLDR; The human body is incredibly complex, and my shoulder/arm/upper back pain came all from my lats. If this is your problem, you can greatly benefit from lat stretches. Below is a video that teaches you how to stretch and do self massage with lat muscles, or latissimus dorsi. For the vast majority of you experiencing shoulder/arm pain - this thread will not apply, but I figured it was worth sharing as it was the central problem around my shoulder and arm pain. And if it happened to me, it is probably affecting couple of you out there. One of the last places you'd look for shoulder and arm pain would probably be the lats. The pain I felt was deep in my shoulder, bicep, and tricep. The pain would occasionally run along my bicep and tricep tendon, and sometimes all the way down to my fingers. When lifting things, such as trash can lids, I'd get shooting pain in my deltoid. When lifting up a case of water and loading it into a shopping cart, I'd also feel dull pain in my shoulder and arms. I went to see a physical therapist, and because the pain was going all the way down to my fingers, they diagnosed me with a pinched nerve in my neck. The therapy provided a little relief, but the pain would always come back after playing badminton. I got tired of wasting money at physical therapy, only for the physical therapist to tell me that I'm good to go back, and the pain reoccurring. Out of a desperate attempt to fix this problem, I went to get a second opinion at a chiropractor, who said I have a shoulder impingement. I looked up the symptoms for shoulder impingement, and there were many symptoms that overlapped. I figured it was a mild form of shoulder impingement, and proceeded to do many shoulder stretches and rotator cuff exercises, but this didn't help at all. Out of sheer luck, I was just showing my wife how much more the muscles in the right side of my body was more developed due to playing badminton, and told her to put her hands on my right and left latissimus dorsi (lat muscles) while I flexed. She said there was a huge difference. As I flexed my right lats, I noticed my shoulder and arm start to hurt. Flexing my right lats would send the pain to my shoulder on and off. Then it hit me. I never once stretched my lats during physical therapy or at home. Everything I was doing was stretching my pecks, neck, and shoulder, but that wasn't where the source of the pain was coming from. I started going on YouTube to learn how to do lat stretches, and sure enough, after doing this for a few minutes, the pain in my shoulder subsided considerably. And it made sense. I just recently started getting back into badminton and I couldn't find my old racket, so I bought a new one that was pre-strung. The string quality was terrible and the tension was far too low, forcing me to exert extra strength into my smashes, which I used my lats to overcompensate. Since I took a 6 year hiatus, I didn't realize that my strings were that horrible. And my strings had the Yonex mark on it, so I figured it was a decent quality string... but no, they just spray painted it on there. This is a weird analogy, but if you imagine you're about to stab something with a knife in a downward motion... right before you stab, you will probably flex that lat muscle to generate more force - that was what I was doing to smash (Yes I know it's bad form and I'm supposed to be relaxed. Very painful and expensive lesson I learned). But this seems to be the problem, and if you have this problem, I hope you were able to find this thread and treat yourself.
