witness statement..Violated Rights??

Hi! I was wondering..there have been two accounts where I was asked to fill out a complaint against someone and I refused, so the police officers asked me to fill out a witness statement and I still refused, so they made me do it anyway...
I was wondering if there is a difference between a witness statement and a complaint, if so, what it does, and do I absolutely HAVE to fill out a witness statement...also, if I do not HAVE to fill out a witness statement, have my rights been violated, if so, what can I do about it?
Please help, court is soon...
OHIO