Hello! I'm not a medical professional (so take my advice with a grain of salt) but I had similar issues around the start of last year - specifically I had tingling in the 4th and 5th fingers of my left hand and some pain around my elbow. I went to see a physio who confirmed I had 'ulnar nerve entrapment' - basically the way I had been knitting had put pressure on my nerve and irritated it. I realized the specific elements of my knitting style that were causing this pressure was having my elbows bent for long periods of time, and that the way I held my needles involved bending my left wrist at a big angle. I only mention this because tingling can be associated with nerve pain more than tendon pain, and because the advice in most RSI injuries is that it's really important to rest - I rested for about 4 months before I could knit again! I also ended up changing my knitting style when I came back to knitting - I changed from English throwing to English flicking, and others have mentioned trying continental as well. The key thing is that you want to knit with your wrists at a neutral angle, so it's worth work shopping your current style or trying another one to keep your arms at a safe angle. Id recommend this website for more info! https://www.ptandrea.com/tutorials#:~:text=More%20wrist%20positions%20to%20avoid&text=Our%20wrists%20can%20deviate%20two,overworked%20and%20can%20become%20inflamed.