Only is often misplaced in a sentence. We must be careful about its usage to avoid confusing our readers. Learning correct usage of grammatical modifiers is a hard work and it is worth all the effort.
Only should go right before the word or phrase it modifies.
“Only I said I cannot attend the party” means that I was the only one to decline the invitation.
“I only said I cannot attend the party” means that I said nothing but I could not attend the party.
You can further explore this minor topic of English grammar at Dailywritingtips.com