I got a two inch scrape on my shin. why does it still hurt a day later when things touch it?

Because scrapes hurt: When you scrape skin, you expose nerve endings, causing pain. It takes several days for a scab to form and cover the nerve endings. Bandaides or other occlusive wound dressings will keep the tissue moist and lessen discomfort. Check regularly for drainage and redness which might indicate infection

Nerve sensitivity ab: The scrape cause irritation to the skin nerve endings. That is why it is painful to touch. This should resolve in a few days.

It depends: A skin "scrape" will go through normal phases of healing which include inflammation and pain. However, the scrape can become infected which could result in increased pain, redness, and sometimes drainage or pus. I suggest you cleanse the wound and apply a topical antibiotic and a band-aid. If the problem does not improve, see your doctor.