the root of mullein, i discovered through reading matt wood's books and jim @ herbcraft.org. it helps to increase the synovial fluids around the spine, making it more pliable -
it is great for back stuff. and healing joints in general, i think. i gave my dad a tincture of mullein root and solomon's seal after he hurt his knee, along with a comfrey and arnica salve and it healed nicely. a friend of mine had a disk removed from his spine years ago, and didn't have the money to continue with many more appts. i think they kept him on drugs that masked his need to rest, now he is in constant pain and maybe the bones spurred or something. but the same tincture mix helped him with the pain immensely.
i use it when i feel my back get tight and tense, like i need to pop it- and because mullein root has nerve sedative effects, i would use it if there were nerve pain too.
for the lubricating effects, someone came to me and said he has back pain, he rides in a dump truck all day and bumps around constantly. he has loved the mix and now swears by the magic of herbs :)
i have been wondering if it would work with urinary incontinence, i don't know, but i read that it helps with young children and bed wetting.

> Then my cough became dry and harsh, and nothing herbal I thought would be helpful yieled any results, except resting.

Next time this happens you might try some hot peppers/cayenne. My mother used to make a chai tea with black tea and other spices, then add one dried red pepper to the mix. I've found that hot peppers really work to loosen a cough and get it away from that dry hacking. (If that doesn't work, I then turn to a purchased expectorant syrup.)