Doctor thinks i have pneumonia.started antiobiotics. fever stopped. heart rate very high (85-100). i'm worried, is it normal?

Pneumonia: It surely sounds like you are having a successful and normal recovery from pneumonia.

See below: It would not be unusual for you to have a mild to moderate increase in pulse rate during early treatment for pneumonia. 85-100 is not a very high heart rate. The fact that your fever is better suggests your antibiotic treatment is effective. If you are feeling better don't worry about a pulse of 85-100. It will return to your baseline after resolution of your pneumonia and any deconditioning.