Good morning, 10 days ago inhad a 1 night stand,
You should checked for chlamydia
I am sorry to hear about your troubles. If it has not been done, I suggest you have either morning urine tested for STDs or a urethral swap, which would also be tested for herpes virus. The soreness in your neck sounds unspecific and possibly viral (flu-like).
Hope this helps. Please let me know if you have further questions.