I would have thought that if it was green it would be something other thant the Mucuus plug as isnt the Mucuus plug a browny/pinky even red colour/discharge.

It is normal to get weird looking discharge during pregnancy and for it to be clumpy. Also it could be just normal aches and pains - though if its quiet painful and down low i would go get looked at and asses by a doctor or pregnancy unit at the hospital.