You are weak and underrecovered.

Short term solution: Rehab. Roll/massage, stretch, mobility.

Long term solution: Get overall strong(er). Squat, bench, deadlift, press. And/or gymnastics style strength for upper body. Stronger = less fatigue = shorter recovery.

In my experience, i used to do much conditioning and little strength training, after massaging people and after carrying luggage for a whole day (travelling), i used to get much DOMS in my traps even though i was already strong enough for the tasks. After doing much strength training and little/no conditioning, the DOMS are gone.

Herman Chauw
Movement coach, strength & conditioning coach, rehab therapist