The leaf color is poor. This is a sign of poor fertility in the soil. They also show signs of having been through a dry period. I would recommend a shot of Hollytone or Miracle-Gro® Shake'n Feed® Continuous Release Azalea, Camellia, Rhododendron Plant Food. I would use at the rate on the package once this year and then at half that rate on the package once next spring.

Be careful. To much fertility causes worse problems.

Both may be getting too much sun. Sample soil and have it analyzed before laying on fertilizer.

Is a camellia.

Although both plants are behind the house, they get little partial shade, full sun most of the time. I don't have any places where are shadier. What do i do then?

If you think they are burning you will have to move them into shade or move shade to them. If none of yard seems suitable maybe give up on them and plant something adapted to situation.

Call your Extension service or check with the University of GA and ask when to prune rhodos in your area.
Get out a bucket and make a 20% bleach solution to dip your clipper blades in. Then prune away the diseased leaves/stems back to healthy growth. Bag the debris and throw it away. After each cut you need to take care to wipe down the blades with bleach solution to sterilize them.

Be careful where you buy your mulch and how much you put on. Mulch could harbor spores of viruses or fungal infections that can be transmitted to rhodos. I have 2 monster rhodos in my yard in full sun and they had this problem starting 2 years ago. I threw out 5 or 6 55 gallon bags of branches and leaves that had the same problems - only worse. They grew back almost all healthy foliage and bloomed on time this spring. I saw today I need to prune some more away at the bottom, but this pruning rejuvenated them also. I took a diseased branch into our Master Gardener program and they thought it was phytophera or root-rot. I'm not so sure but the hard pruning got rid of the diseased growth.

Prune rhododendron after blooming. Now is very late and would reduce the bloom next year. It wouldn't hurt the plant, just reduce the bloom. Always prune and remove diseased material and remove diseased leaves that have fallen off. I wouldn't worry about the leaves with spots if they haven't gotten any worse.