Most kids don't fight you about things without a reason. You are doing the right thing by asking questions and trying to figure out what is really wrong. You are not alone! My son also had trouble with both of these things and at 13 still sometimes complains about bathing.
Going to your doctor for the bed wetting is a great idea just like the other moms have said. There are so many reasons for bed wetting. Sometimes it is physical or emotional. My son's problem was linked to his sleep apnea. He did not have a physical problem with his bladder but when he would stop breathing in the middle of the night and gasp for air, he would sometimes loose control of his muscles. When we got his tonsils out for his sleep apnea the other problem cleared up.
The shower thing might be emotional like some of the other moms have mentioned or it might be physical. I am a preschool teacher and have a son with mild asperger's syndrom. Over the past few years I have been reading material on sensory processing disorder(once called sensory integration dysfunction)for both my on son and some of my students who experience this. My son is more sensitive to outside stimulation. He is bothered by hot and cold foods, the feel of some sheets and clothes, the shower, sunlight, the wind or AC blowing on him. Others are less sensitive and don't notice bumping into things, temperature changes, hunger, or the need to urinate. Then there are some who are both over and under sensitive. You can also ask your doctor about this or talk to your school counselor. If your daughter seems like my son there is a good book called "The out of sync child."
Every child is so unique and wonderful. I hope you find what helps with your daughter. :-)