Once you start taking the antibiotics, you will likely see a pretty rapid change in symptoms. Normally a bit better within 24 hours and significantly better in 48. If you still have it in 48 hours, then check back in with your doctor. Make sure to finish the full prescription though. And if you really are very worried, you can call your doctor and ask too. Most likely the antibiotics will work to make you feel better in every way including the neck issue. Strep stinks!