Mello - I would certainly get another opinion on tongue tie. There is a massive thread on here full of people who were told over and over that there was no tongue tie, only to find out later that there was. I think somebody had 7 differnet HCPs tell them no tie until they found one who knew what they were doing
Posterior tongue ties get missed by many, many HCPs who don't know how to identify it. If they don't know what they are looking for, then the tongue can look completely normal.
If at all possible, I would recommend either of the dentists named earlier - Malcolm Levinkind or John Roberts. They both trained with Dr Kotlow who is a world leading expert (have a google!)