With flu season in full swing, sore upper arms abound. ... Why your arm hurts so much after getting a flu shot . Nov. 14, 2019 at 6:00 am Updated Nov. 14, 2019 at 7:42 am . By .

Q: After receiving my first Moderna booster, I experienced severe pain in my left arm and assumed it was temporary. However, the pain has not dissipated from the shot location. It’s been more… ...