I have some great advise about that mold.....the CDC (Center for Disease Control) or the FDA (Federal Drug Admin.) out of Atlanta, GA and San Francisco respectively will allow you to send them a sample of the mold you scape off of the wall and check it for you for free to ensure its not "black mold" one of the deadliest....and i am pretty sure that it can have adverse effects on all parts of your body including lung and heart. You may be feeling that your heart is beating faster at nite because there is nothing going on around you, quiet, calm. no sound and that is the most typical time that all of us notice things. In the daytime we are too occupied to notice it unless it is severe. I would look at how long you've had your pillows on your bed and the condition your mattress is in for the sore L. arm and shoulder. You may be out of alignment w. your sleep pattern . If in doubt spend the 50.00 for a consult w. a heart doc to give you a little mental relief......
Starting at the end, Mold can be a serious problem, depends on how much there is. Remember it can be behind the wallboard, not not visible. So if you have some visible mold, at least try to kill that with diluted laundry bleach.
You need to get some numbers as for as you HR goes. For some range numbers: at rest a HR between 60 and 80 would be very good, anything less than 100 is mostly acceptable. Walking around a HR in the 100 to 110 would be good for most people in average physical shape. A rest HR 130 or higher would make me want to see the doctor for a check. A rest HR over 200 that lasted more than a minute would make me think about going to the emergency room
Not sure the above is of any real help, but if you get some numbers and the conditions under which you measured them (rest, walking, running...) you may get more substantive replies.