Is spectrum text is painful or not.?

I am married but haven't got child I planning to go for check up very soon I wanna go for medical check up with my husband but most of the doctor wanna do the spectrum test that usually put in vaginal and scan.Before that they used to scan only in stomach but then people saying they might be doing the spectrum test, some of them are did and they saying its not hurt, But my problem is hubby's penis doesn't in fully into my vaginal, it only goes half head, however i try also it never goes in fully in this two years never get any improvement so is that spectrum check will be painful and is that will goes very in my vagina is that could be hurt I am getting nervous and phobia on it. Anyone who did that spectrum check please do advice me. I need this advice please do care advice me.