Thanks for your query.
I read your query and I understand your concerns.
Following is my reply:
1) The neck pain
you are describing is totally unrelated to the medicines you are taking.
2) It is must be due to some physical injury
or some change in sleeping position , pillow size etc...
I hope I answered your query. I will be available for any follow up query you have.
Dr. Mahesh Koregol
IVF & Infertility