Answer:
Tickle with your fingers and a song it will sing. Be careful, though, you may break a string. What is it?
A precious gift, yet it has no end, no beginning, and nothing in the middle.
I am your mother's brother's only brother in law. Who am I?
What pulls you down and never lets go?
Break it and it gets better, immediately set and harder to break again.
My days are numbered. What am I?