Really love doing OHP but every week I have neck pain the day after, what am I doing wrong and what is a good substitute for OHP
What are you doing with your head when you are overhead pressing? If you are leaning your head forward with your chin down that would probably hurt your neck.
This is common when having some type of thoracic/cervical dysfunktion.
The link above it probably the next best thing, when as it shoots wide. Seek a physiotherapist if you want the best thing for youself.