stiff clutch

My 06 M3 has 18k miles on it. After sitting for about two months the clutch pedal felt really really stiff. Some driving has losened it up a fair bit, but its still stiffer than normal. Sometimes it feels almost Ok the next pedal press it feels stiffer. Any idea what this might be and how to fix?

Given the low miles, you may an issue with the clutch slave cylinder. The internal seals may have been damaged due to sitting in the same position while parked for extended periods of time. You can try flushing out the fluid before replacing parts