after you beat sudowoodo go to the left there is a fat guy in blue he gives it to you
you cannot get rock climg in crystal because it is disvovered in 4th generation and the game of pokemon crystal compromises the 1st and 2nd generation so you have no chance of getting rock climb also it is of no use here.
in route 36 after you have defeted or captured sudowoodo
It is in Rock Tunnel.
Rock tunnel Uncommon
In Pokemon Liquid Crystal, you can obtain HM Rock Smash by speaking with a man in Violet City. He is located near the Pokemon Center and Sprout Tower. After receiving HM Rock Smash, teach it to a Pokemon that is capable of learning the move, and then you can use it to smash rocks blocking your path.
Go to where you caught/battled Sudowoodo, and to the right, there's a fatty who gives it to you!
Pokemon crystal? Well...in Pokemon Diamond it's a stone dice that powers up rock type moves.
If held by a Pokemon it will increase the power of rock type moves such as rock slide or rock throw. Giving it to a rock type Pokemon is highly suggested.
rock throw
The rock tunnel can be found by the power plant (east of Cerulean City. You have to cut a tree to get to the path and then follow the path and you will find the entrance to the rock tunnel right next to a Pokemon Center). The rock tunnel leads to Lavender Town.
A TM located through out the world.
Sudowoodo can learn it just lvl up