Hi.. Thanks for the query.. Pain in lingual frenulum along with pain in tongue with numb feeling of the lip can all be due to inflammation inside mouth causing pain.. Eating to much of sour candies or any other sour foods can cause irritation inside mouth, so first of all stop eating them.. Hurting of upper part of neck can be due to swollen lymph nodes and it can be due to inflammation or infection inside mouth or salivary glands.. You should also consult an Oral Physician and get evaluated so that a clinical checkup of the oral cavity can be done so that the exact cause can be ruled out.. For now gargle with specialised mouthwash like Magic mouthwash, do cool water rinses and suck ice pops.. Take Vitamin B complex supplements.. Take painkillers like Ibuprofen as it reduced pain and inflammation.. Avoid spicy and hard foods and take a soft and bland diet.. Hope this helps.. Regards.