If i get a lingual frenectomy surgery i have seen people putting their tongues at the back of their throats im not getting the surgery this is just a example and a question but is it possible that you can die by doing this?

No. You cannot die by making your tongue fold back into your throat.

Lingual frenectomy surgery, usually done at birth to allow normal range of motion. Touching back of throat w tongue is abnormal, but not problematic. If your Physician or Dentist has recommended procedure, go for it. No, post surgery you will not have that range of motion. And no, people do not swallow their tongues..