Had the Oxford AstraZeneca on a Tuesday, same sore arm and stuff. Woke up the Wednesday feeling generally out of sorts, groggy and often experiencing chills. Pain in the arm had gotten worse. Thursday I was feeling better but the arm was still very painful, this continued trough the days and then on the Sunday my fiancé (@SgT.Chris) noticed a small rash on my arm. On closer inspection the injection site was also pretty swollen. Was going to ring the GP on the following Tuesday but I woke up that day and it had all gone, the rash, the swelling, the pain, just poof.
In retrospect it's possible it was a mild allergic reaction, I'll bring it up when I got for my second shot which for some reason isn't scheduled till May despite the recommendation being 3 weeks.