guitarist1977

As everybody else suggested - Relax.

Your fingers should be flying over the fretboard like a butterflies not barely moving all tensed. Don't put more pressure on the strings than needed for the strings to sound and it is actually not too much. Put your fingers all relaxed on the strings, just touch them very lightly (if you try to pick that string it will be muted). Then gradually press the string with one finger so it is half way to the fret (string will be muted), then relax to the original position. Do it several times. Next from the relaxed position press string with one finger until you can get note sound from the fretted string. This is as much pressure as needed to fret the notes. Do it several times with each finger. Of course do it very slowly.

Or another advice - find a good teacher.

There is a great book that I found recently - The Principles of Correct Practice for Guitar by Jamey Andreas. It solely focused on hand relaxation, hand positioning and correct movements. There is also a video by this author.