I can only answer in terms of my field of expertise, as a Chiropractor, and will try to give you the range of possiblities that your description of your symptoms suggest. As always, it is best for you to consult with a GP and a Chiropractor in your area, to confirm a diganosis and get proper care.

Very often, people who suffer from arthritis have worse pain at night, when they are sleeping. This derives from the fact that you have less active movement and therefore less circulation in the night, and places that might get less sore during the day act up while you are sleeping.

Simply explained, arthritis means changes in the joints, and can be either genetic or due to normal wear and tear throughout your life. Your other symptom, of sharp pain in your legs when you try to touch your toes, could suggest that these changes in the joints have also caused some level of disc irritation, as well as some impingement of the nerve that travels into the leg.  According to the principles of Chiropractic, pain in the extremities (legs, arms etc) very likely have their derivation in the spine, where the message so to speak begins; and so by re-aligning the spine, you relieve pressure on other areas, and increase overall function, without pain.

There are of course other options, depending upon your family health history and your history of various trauma to the body.