Lower back pain after starting workout.

[StarStuff18]

I am a 20 year old female with height 5'7" and weight 95kg. I started going to the gym around 2 months back and my trainer got me started on a high intensity of squats, steppers and abdomen related exercise such as squats and sit ups. And after about 2 months I developed a back and knee ache. My left knee hurts whenever I climb stairs or stand up from a sitting position but that pain is much more better than before. My back ache though, there's this pain in my lower back of the right side of my spine which is only there where I bend forwards, when I stand up from a sitting position, when I change my posture while sleeping and when I sneeze while standing up. Along with that if I bend to pick up something heavy like two or three books from the bed even, it hurts then too. And the pain sometimes feels like shooting down my right hip and leg but that's very rarely and the pain is barely noticeable but it is there at time. I've not been going to the gym for almost 3 weeks now but this pain is not settling down. At first it was throughout my lower back but now it's just along where I mentioned earlier. It'll get great to get some help or the other. Thank you so much.