Lordisis refers to the concave curve in the lower back. With a hyperlordotic posture, this curve is exaggerated it is usually due to tight/shortened hip flexors, especially iliopsoas & also rectus femoris. These muscles being short increases the distance between the ischial tuberosity (bottom of the pelvis), which is the origin of the hamstrings, and the hamstring insertion points of the lower leg.
This type of posture usually causes tight and sore, possibly painful, hamstring muscles. Some people assume, incorrectly, it is a hamstring problem and so carry out extensive hamstring stretches. This usually makes matters worse as lengthening the hamstring muscle, which is already being stretched to its limit, allows the hip flexors to become even shorter.
A secondary issue that is common with this posture is that the lower portion of the erector spinii (the muscular columns beside the spine) become short, so this usually needs to be addressed.
The treatment strategy would be to lengthen shortened areas mentioned above, using soft tissue release techniques and PNF stretching.