4 yr old who throws major temper tantrums has multiple meltdowns everyday. Can get physical with you at times. What can/should be done? Desperate!

Talk to your doctor. First, talk with your child's doctor. She may recommend a child therapist or behavior counselor. Give your child choices where you can, but not where you can't. You can say "it's time for bed. Do you want to read a book or sing a song before you go to sleep?" don't say "do you want to go to bed"! avoid unnecessary power struggles and choose your battles. Be consistent with important rules, though.
Behavioral psycholog. You should start with a behavioral psychologist. If strategies do not help, a psychiatrist may be able to prescribe a medication to help deal the behavior.
Lack of emotional. regulation + aggression suggest a Neurodevelopmental or Childhood Dysregulation Disorder. Call your school district's Child Find for evaluation for Early Childhood Special Ed. See a child psychologist, psychiatrist or developmental/behavioral pediatrician & seek family therapy to insure (s)he gets no positive or negative attention for tantrums & sees/hears no aggression at home or on TV/videos.