grammar problems

If I would say “I have had some problems with the grammar” Is that a correct one?
If so, then plz tell me why “Have” and “Had” sits consecutively?

regards, Shopgirl.

I have had some problems with grammar.

That is fine. ‘Have’ as a main verb (meaning ‘possess’) functions just like any other verb in forming the perfect tenses with the auxiliary verb ‘have’:

I have had my car for two years.
I have seen the movie.
I have visited Turkey.