Can looking up and jumping and then getting pushed from behind break your neck? i heard a crack but no pain or anything else?

It is highly unlikely, Had your neck broken, you would not have been able to send the message. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. Get HPV and Covid vaccines. Wish you good health!

Unlikely to break bone, but other things can cause cracking sounds in the neck or joints. If no pain or symptoms, then unlikely to have a broken bone.