I have heard that it is disrespectful, while praying, to start a Surah with the word 'Qul' which tells Allah to 'Say' such as in Surah Ikhlas, Naas and Falaq. Is it allowed to recite these chapters without the first word 'Qul'?
This is unfounded as for starters you are not telling Allah to say, rather this is Allah's words addressed to the Holy Prophet (s) and the believers. It is highly recommended to say surah ikhlas in prayer and it is disliked to abandon this surah for a whole day.