What to do if i am 23 and have just found that i have two osteochondromas in my left shin. am i likely to have surgery?

Depends on a number: Of factors, like the size of these osteochondromas, their exact locations, any symptoms associated with these lesions, like any pressure on adjacent structures. Xrays/ct scans maybe needed. See an orthopod to get treatment options outlined for you, depending on your symptoms. Some of these can be just watched, others might require surgical removal. Good luck and happy holidays.