Gross hematuria (blood in urine) visible to naked eye is seen in
kidney and bladder
stones, cancer of
kidney, UTI or urinary tract infection, sickle cell anemia, bladder endometriosis (in females), low platelet count, bladder injury and bladder infections. Apart from urine examination, you would need some other blood tests, imaging tests and maybe cystoscopy.
Since you also have a sore throat, a streptococcal infection involving both the throat and the kidney should also be looked into.