Can a cavity cause throat agitation which makes throat feel inflammed tooth dosent hurt but half of it is gone n blackened can't afford dentist?

Yes: You do need to see a dentist. The tooth may be abscessed and can cause other serious health problems. Throat agitation with sleep disturbance could also be obstruction sleep apnea. If you can not afford a dentist, check around for a clinic where free or reduced fee care is available.

Yes: You may be cutting your tongue on the broken tooth, causing the inflammation. It needs to be treated. Call your local dental society for guidance to low cost dental clinics in your community.

Yes: You have an infection and it's spreading. If you had an infection anywhere else, would you refuse to treat it? You now have an infected throat as well as tooth. It will continue to spread, at an ever expanding rate. Seek care @ University Dental School. Work out payment plan w private Dentist. Call Social Services or Dental Society for reduced fee clinics.