It appears you may be experiencing gingival recession, a condition characterized by the loss of tooth enamel often attributed to factors such as improper brushing techniques, the use of hard-bristled toothbrushes, or certain habits which gives you symptoms like Sensitivity or sometimes pain if the tooth wear is severe affecting your pulp (living tissue of a tooth).
Next Steps
If you experience severe throbbing pain or night pain,you might need a root canal treatment.
It is advisable to seek consultation from a local dentist to assess and address any potential presence of deep cavities contributing to your symptoms.
Health Tips
Use a desensitising toothpaste like Thermoseal repair on the affected part with a clean finger and keep it for few minutes and then rinse off.
(This won’t help if it’s a deep one**)