You may not like my answer....but...if you have SLE and this is a NEW symptom that has not been dx'd by by your doctor - tell your doctor and see them ASAP.
I had a fairly serious issue that needed treatment and the symptoms were just like yours. That doesnt' mean you have it....but you need to check it out.

I was told if there is any chest pain, pressure, discomfort, or back pain go to the ER right away, otherwise it could be any number of reasons all worthwhile to tell a doc

Vitamin D
Hi, when my vitamin D level was low (17 ng/ml), I used to get this symptom frequently. After I got my vitamin D blood level to 75 ng/ml and kept it there, this and many other symptoms either greatly improved or went away. But vitamin D is a hormone and acts slowly, and it took about a year to figure out how much vitamin D I needed to keep my blood level up. I learned that researchers found that we need 1000 IUs for every 25 lbs of body weight as a maintenance dose and double that for a year if a person is very deficient. A person is very deficient when the blood level is less than 20 ng/ml. I then found in a newsletter on www.vitaminDcouncil.org that people are generally very magnesium deficient and that vitamin D and magnesium work synergystically. Vitamin D enables magnesium absorption but vitamin D also needs magnesium to function. I was getting muscle twitches and was found to be magnesium deficient. I added 400mg magnesium oxide per day sometimes twice a day. My health overall improved about 50 % by correcting these two deficiencies. Be sure you don't use any supplement as a substitute for medical care, though. For example, I still go to my doctor for periodic checkups. I also learned that there are two types of vitamin D, D2 and D3. D2 is frequently prescribed by doctors and is the plant form. D3 is the animal form. Some say that D3 is better. I hope my story helps.