Why Does my 5 month old child cry in her car seat?

Every time we make a road trip whether it's to the grocery store down the street or traveling are 5 month old starts crying in her car seat. She will not stop till we stop the car and get her out. she has cried from the time we brought her home from the hospital to now. her nonstop cry and, screaming drives me crazy. I tried everything We have stopped and feed her, even tryed changing her. Still she crys the whole time. We have tryied music lights & toys. blankets, sun shades, 2 different car seats, we Have checked the straps and the positition of the car seat. I have even had my husband drive so i could sit in the back with her and that dont help she still crys.i have tryed taking her when she is tired and hoped that she would sleep the hold time. i take took her when she has had a good nap and still she crys.She starts crying as we start the car. Not even moving. Any ideas why You name it, we tried it, and nothing worked