Trapped gas in lower abdomen at 6 weeks pregnant with constant pressure hurts to move is that a sign of miscarriage?

Not likely. Pressure is not typical for early misscariage. The sign of impending misscariage is vaginal bleeding with severe cramping abdominal pain.
Not likely. Miscarriage is at this stage is more likely to feel like regular menstrual cramps. If you're pretty sure it's trapped gas, then it's more likely to be the slowed gastrointestinal motility that many women experience due to the rapid increases in hormone levels supporting the pregnancy. Massage of the lower abdomen while changing positions in bed may help some.