Your symptoms of “numbness in the front of my thigh also my knee is aching also and my groin just throbs” is the dermatome (nerve distribution) of the L2-4 nerves.
Your MRI notes a large disc hernation at L3-4 compressing the L3 and somewhat the L4 nerves. This fits your current complaints. You have some other degenerative changes but your primary pain generator is most likely this large disc herniation.
If you have pain as your only symptom and not motor weakness, then a good therapy program and an epidural steroid injection would be the first steps in treatment along with some temporary medications.
If you have motor weakness, in my opinion, you need a surgery to decompress this nerve root. See lumbar microdiscectomy on this website.
You can test your strength at home with these two simple tests. If your quadrates femorus muscles are weak (the ones in the front of the thigh that straighten your knee), you will know by this test. Stand next to a counter facing it and rest your hands on the counter. The hands are not to be used to hold yourself up unless you feel like you are going to fall.
Lift up your painful leg and do 10 deep knee squats standing only on your good leg. Try to squat down with the knee bent at least 90 degrees. You will then understand what a normal response to this test is with your good leg.
Try the same activity with your painful leg. If you have motor weakness, you will find that after one or two of these squats, you will be “stuck” and not be able to rise up unless you use your hands to help you. This is why you need to make sure the your hands are on the counter as falling down is common without additional support.
A positive test (inability to rise up after a number of these squats on your bad leg) is an indication of motor weakness and the need to contact a spine surgeon.
The other test is toe raises on the bad leg. If the L4 nerve is affected, you might have weakness of foot dorsiflexion (the inability to raise your forefoot up). Position yourself just like you did to test the quad muscles but this time, do 10 forefoot (toe) raises with your good leg. Then do 10 of the same with your bad leg. If you cannot complete ten with your bad leg, you have motor weakness of this muscle.
Dr. Corenman
Donald Corenman, MD, DC is a highly-regarded spine surgeon, considered an expert in the area of neck and back pain. Trained as both a Medical Doctor and Doctor of Chiropractic, Dr. Corenman earned academic appointments as Clinical Assistant Professor and Assistant Professor of Orthopaedic Surgery at the University of Colorado Health Sciences Center, and his research on spine surgery and rehabilitation has resulted in the publication of multiple peer-reviewed articles and two books.