Bleeding from a caries hole!

A sharp pain has been lasting while blushing at the portion of the left lower second molar, ducal distal corner at Dentin-Enamel junction so class 5 including distal surface must be the disease name.
The last time when I visited the dentist's, some bleeding was found in the bottom of the caries hole and anesthetizing did not take effect, so the young dentist said let try next time because removing infected pulp tissue should proceed under no anesthetizing condition. Though he said so with smile to relieve my worry, he looked me like a black Satan at all, he called me up this morning asking me when do I come next, call us back to make next appointment with his receptionist.
To tell the truth, my i-Phone is very heavy to call him again, though his office is designed blight and clean, but actually nothing but Hell.
Supposing I'm laying down on the Dentist's operating chair with no protecting and no resistance, my pulse counts faster and faster, how come?