No. Posture Plus is a wellness and awareness tool. It doesn't diagnose or treat any condition.
The neck load figure is an estimate from a commonly cited model of how heavy your head is for your neck at different angles: about 5 kg upright, 12 kg at 15°, 18 kg at 30° and 27 kg at 60°. Your own body may differ.
If you have neck or back pain, talk to a doctor or physiotherapist.