Answers to Science Questions

How do painkillers target the parts of the body that feel the pain, and why we don't just go numb in random parts...

If I wake up with a raging hangover-induced headache, is aspirin a miracle cure, or will it make things worse? I'...

Does a healed fracture result in a stronger bone?

What causes muscle cramps, and are there any cures?

And what's Stephen Hawking's explanation?