I thought I was going mad until I saw a similar post on the apple forums:
https://discussions.apple.com/thread/7026458
Please see the post from Mstattedcanvas on page 1.
I've had my 42mm SS ML since launch but whenever I wear it I get a dull pain in my arm, slight tingling and a bit of numbness! Don't understand it and thought I was going crazy but no someone else has posted a similar thing.
Has anyone experienced this with any of there AW's?
Another post : https://discussions.apple.com/thread/7029361
I had the same experience when I purchased the Apple Watch Sport (antique white) on December 23. After only wearing it for about half an hour or less I noticed a deep tingling and then a slight pain in my arm. I thought I was crazy. I switched to my right arm and within minutes the same thing started to happened. The longer I wear it the higher the tingling and pain/discomfort went up my arm, all the way to my shoulders and neck. I loosened the band....no change. I stopped wearing it for 4 days, then put it back on and the pain started all over again. I found your post after searching the web to see what I could find to see if anyone else is experiencing the same thing. I ended up returning the watch. I'm really disappointed because I LOVE the watch and I am a loyal user of many Apply products, I love the company and the brand. I don't know what could be causing this. I tried to force myself to wear the watch all day and HOPED that didn't feel anything because I wanted to keep it so badly, but I couldn't ignore the pain/discomfort. I just wanted to respond to your post to let you know that you aren't alone.