Thumb hurts when riding

My thumb hurts when riding. I get these marks on my hands from Alpinestar LG size gloves(one size up from what they recommended me based on sizing chart.) I don’t think I’m holding my handlebars that tight but could that be a reason why? I get marks on the left hand as well but most of the pain just feels like cramping on the throttle hand. This came from only a 20 minute ride.

My thumb hurts when riding. I get these marks on my hands from Alpinestar LG size gloves(one size up from what they recommended me based on sizing chart.) I don’t think I’m holding my handlebars that tight but could that be a reason why? I get marks on the left hand as well but most of the pain just feels like cramping on the throttle hand. This came from only a 20 minute ride.