What type of thermometer do you have and where exactly is it measuring?

The heat pad by itself will create your hot side/basking spot. Heat pads only heat surfaces, because of this you need a probed thermometer with the probe directly over the heat pad on the floor of the cage to measure the hot side temperature. This is also why you need to keep your substrate layer thin. Heat pads do NOT heat the air in the cage. That is the job of the heat lamp. The air in the cage can be the same temperature throughout the cage as long as the heat pad is creating a 90 degree hot spot. I would recommend centering the heat lamp on the cage.

Where is your thermostat probe?

If I didn't explain this well enough just let me know.