Cook pasta shells according to package directions in a large pot of boiling, salted water. Once cooked, drain the pasta and return the pot to low heat.
Add the cream cheese and evaporated milk, stirring until the cream cheese is melted. Add the cheddar cheese and stir until melted and well combined.
Add the pasta back to the pot, stirring to coat with the cheese sauce. Taste and season with salt to taste.
Notes
If the sauce is too thick, add a few more splashes of evaporated milk until you reach your desired consistency.