How Lord Shiva got his bow called Pinaka (पिनाक) ?
There are many stories surrounding this claim. In Mahabharata Shantiparva chapter 289 verse 18, it is mentioned :
आनतेनाथ शूलेन पाणिनामिततेजसा।
पिनाकमिति चोवाच शूलमुग्रायुधः प्रभुः।।
The Lord Shiva pressed his trident ( त्रिशूल) with his hand and thus the trident becomes a bow (धनुष) called as “पिनाक”
One name of lord Shiva known as “पिनाकी” is derived based on this पिनाकोऽस्त्यस्येति ( the one who have “पिनाक”)