What does it mean when i get pimples after shaving?

They aren't pimples, they are most likely razor bumps or "razor burn". Some people just have more sensitive skin and therefore are more prone to get razor bumps. If your shaving gel is scented, that could cause irritation as well. Some have reactions to fragrances. Try an unscented sensitive skin shaving gel. Make sure your razors aren't old, the blades can become dull.