They could not understand how her heart was aching all the time, with a heavy pressure that no sighs could lift off or relieve, and how constant exertion for her perceptive faculties was the only way to keep herself from crying out with pain. 
They could not understand how her heart was aching, with a heavy pressure that no sighs could relieve. Constant exertion was the only way to keep herself from crying out with pain.
