Low back pain. Enough for this issue?

I have started my exercise for cholesterol control like stand jacking,30 min walk ,push up& Toe Tuch.i have overly done toe touch that means 40 reps with 3 to 4 set daily atmost 3 weeks then minor back pain started also 55kg inverter battery I have lift up to my knee level and walked 5 step between only one time between this 3 weeks...pain symptoms like stiffness ,light pain in L4,L5,S1 AND top of butt also some time in middle back..almost 2 months gone now weakness also feeling...Tried diclo gel and heat massage also pain relief tablets 2 sets. then taken MRI from that mild diffuse bulge observed in L4 to L5 and L5 to s1 also straightening of lumbar lordosis noted..which one caused this bulge toe touch or battery lift or this mild bulge already existing as like common...pls help to clarify...is stretching exercise enough for this issue? Pls suggest..MRI report attached