practice will give you tougher fingertips..
check how you hold the guitar. make sure you do not roll it too high when your looking where you place your finger.. You can also raise the neck higher that will give a little different angle for your wrist..
try going from a C to F and back to C .. that is basiclly rolling your index finger down to cover the F fret and stepping middle and ring finger from the E and C to the A and F .. Just relax and it will come to you soon.. then threw in the G chord
link to - (CFG progression)
http://www.guitartricks.com/lesson.php?input=11137&c_id=1&ch_id=6&s_id=441
You'll probably get more tips This is one of the most talked about chord problem...
Good Luck and keep on pickin'
Gordon