You need to remain aware of your body throughout the meditation, making adjustments when necessary. Some pains can be danger signals - don't ignore pins and needles or numbness. It is not good for limbs to become completely numb. Sharp pains also indicate that something is wrong. If you are in any doubt about pains in meditation, talk to someone with more experience. If you ignore danger signals, you run the risk of damaging your body.

Some slight pain is inevitable, like discomfort and itching and so on, but most pains are caused by poor posture. Although you can't simply rely on whether or not your posture feels right. What feels 'right' is often just what you are used to. So when a friend or teacher places you in a better posture it will probably be unfamiliar and may even feel awkward at first, but stay with it.