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Hello, I have 8 months of training in Muay Thai going on 9, but I still can't overcome this problem, and I don't know what to do Every time I'm Boxing or practicing my punches on the heavy bag, after at least 5 minutes on the heavy bag, the muscles in my shoulders and traps get sore, forcing me to lower my hands and give my shoulders a few seconds (at least 5 seconds) of rest before putting my hands up again to protect my head and chin. All these months I've been enduring the pain from the muscle soreness, have been getting better at enduring the pain from the muscle soreness, but I'm getting tired of enduring it, I don't want the muscle soreness to happen at all, I checked with a doctor everything was fine with my body, so why is this muscle soreness happening ? can someone please help me ? Is this even normal ?