While there are a lot of movies filmed in South Carolina, there are not that many filmed in Myrtle Beach SC. I could only find a record of five films:

Chasers (1994)
Don’t Make Waves (1967)
Shag (1989)
Swimming (2000)
Wild Hearts Can’t Be Broken (1991)

The funny thing is, Don’t Make Waves, starring Tony Curtis was actually set in Southern California and was promoted as a beach film. I guess they didn’t care which beach!