Since how many days are you suffering from throat pain? How long since your voice has changed? You may be started on antibiotics, antihistaminics and medication to relieve the pain, if any.
If you are able to take orally, it is preferable to take oral medication. Prescribing injections and treatment without a through history and examination is not possible.
Next Steps
Please visit an ENT specialist for diagnosis and further management.
Health Tips
Please take plenty of fluids and rest.