Winstrol and back pain

i take 40mg a day, on week 6....i noticed that ive cut up a far bit, and feel a little stronger than usual, ive had no negatives, still get a raging hard-on, no acne,no depression, no back pain, just feel good.....don't know what every1 is talking about when they say they've experienced all these negatives and they are taking so small a dose! nearly finished my course now gunna come off for 2-3 weeks..then start my new course.....i have some test 400mg/ml...think i will do 400-500 mg a week, split into 2 injections, and was thinking about adding some more winstrol to it..and see how i get on....i train hard...but im new to using steroids...could do with a little help?

i am having back pain,maby sb can say how i need do?I think sth to do with my kidney.