Naturally, it is very, very unlikely that person will have too high DHT levels, it may be on high level (tough I'm pretty sure its rare) but body can convert DHT easily to some of the (less active) metabolites and I think it can then expel them as well (via sweat, urine, etc) and I beleive with proviron is the same case and that is one of reasons that with proviron you cant really build mass.
With other DHT derivatives you can have similar or different scenario as they convert to different stuff, really. And it also depends on enzymes of person using it, plus receptors "refresh rate", levels of desensitations etc...

Joint pain on arimidex and other AI is common thing but does not always present itself, sometimes person can have clicky joints or bones etc... Taking vitamin d can prevent or reduce pain, and maybe you're getting lot of it, also if you have source of xenoestrogens (plastic) which act as estrogens in body AI will not have effect on them.
Also painfull joints can be sign of low cortisol level.

Generally, symptoms of low and high E2 can be difficult do distinguish, and neither option is good. Lowering E2 can result of lowering of bone density, and usually spine is the first victim. Never keep E2 too low, and preferably use exemestane/aromasin asit does not have rebound effect, and also if too low, estrogen levels dont take too long to return to "normal" and it happens gradually, while on arimidex one can be on emotional rollercoaster.