hi,
As your weight is 135kg with the age of 18 years, you must focus on losing weight first. Because of this you might have weak abdominals and contracted back and core muscles. As you were having radiating pain your left leg, start doing Nerve Mobilization Technique. just take one MRI to know the level of nerve lesion and get back to me
Next Steps
Avoid prolong sitting and prolong standing. Do regular back and core muscle stretches.