I have severe asthma and i was locked in a one man cell at prison, and the vents were covered with mold. i had to stay in the cell 23 hours a day for 5 months. what kind of damage can that do to my lungs with asthma. i was untreated?

Some or none. To establish any negative effect (change from baseline) and attract the interest of a lawyer you would need pre & post incarceration x-rays and pulmonary function tests. In the absence of demonstrated new injury they are unlikely to take a case on contingency & not be a good investment to you on a fee basis.

Definitely not ideal conditions. Cough is a symptom that may be due to a variety of conditions and proving that in your case was due to mold only would be difficult, but not impossible. Work up will be needed providing you are left with chronic symptoms.