Having too much sodium will cause high blood pressure as you get older.

MSG is less sodium compare to salt. If you cannot take moderate, MSG offers less sodium.

Both will cause your throat dry up and drink more water.

Salt is sodium chloride.
MSG is monosodium glutamate, so yes, both contain sodium, and people are advised to reduce the sodium in their diets.
While both have sodium, they don't have it in equal amounts