"Do inmates at a local county jail (wisconsin) have any legal rights to receive prescribed medications - while they are in jail?"
With some exceptions yes. Basically the jail must provide life sustaining medications: hypertension, diabetes, heart disease. Where it becomes a "gray" area is the other types of medications you mention.
"There are many who have prescribed pain pills, attention deficit meds, diabetic etc who are not receiving proper dosage (times per day or amounts per day)."
Pain medication that is taken daily is likely not required to be prescribed by the jail and dosed. ADD does not need to be treated in jail either. The problem is pain medication that would cause withdrawal is narcotics and ADD meds are amphetamines. Neither of which the jail is going to stock due to the regulations on those medications with regards to storage safeguards, dispensing laws, and high rates of abuse rather than true treatment.
"The meds are often withheld, without the inmate seeing a doctor or nurse, and no written communication for why the meds are discontinued."
The other issue is most county jails have an extremely small pharmacy and limited budget. It just isn't possible to stock the formulary with every conceivable med an inmate may be on in the outside world. Even hospital pharmacies do not stock every drug manufactured. If it isn't on the formulary then the jail likely does not have to provide it special for an inmate.
"Some inmates are going thru withdrawal - leading to depression, some of the med withdrawal also has personality changes tied to them such as hositilty and aggression."
That is one reason why going to jail when addicted is a bad idea. Even inmates on illegal drugs who go to jail go through withdrawal. It is a consequence of the poor choice.
"That's just my opinion, then again I might be wrong." Dennis Miller