Chickenpox along with pregnancy is quite awful, I understand: but some pain in abdomen is common in pregnancy especially the first, due to stretching of the uterus; afer all it grows from a fistful to housing an entire baby! You may try lying down in right or left lateral position if pain occurs. If pain is severe or accompanied by tightening of uterus (contraction) then please consult your obstetrician. As for chickenpox, you may apply sandalwood powder to affected parts, rub lightly, soothes the itching feeling and feels cool and fresh also!