If you got ultrasound
and blood test
done for pregnancy
showing negative results , the lady who touched your abdomen and said that you are pregnant seems to be wrong as the hardness can be due to muscular stretch and fatty or gaseous distension.Burning sensations can be due to Vit B complex deficiency and beatings of muscles can be due to calcium deficiency
or strain on muscles.It is better to visit an obstetrician for per abdominal examination for the reconfirmation.