What could be wrong with me? When I eat too much salty food I get foot swelling. Bp normal.

Retainig water. Salt causes increased water retention in the body.
Salt and edema. You are describing mild edema; this occurs from excess salt and when feet are in dependent position - such as sitting and standing - you may have a kidney condition that makes you prone to fluid retention; you need an evaluation;
Fluid retention. Any type of salt whether sprinkled on or already in food can result in fluid retention.
Sounds like BP. Still could be too much salt even if your BP is normal.
Normal reaction. Eating too much salt causes your body to retain fluids, which is a problem for people with heart conditions. Drinking plenty of water and limiting the salt in your diet, along with regular exercise, can improve your swelling.