HI, dont know how long you have been like this and what led you to this point. But you sound like you have sciatica.. which is often a pinched nerve (nerve compression) either stenosis or you have a bulging disc somewhere in your lower lumbar.. at L5/S1 or L4/L5 usually.
Many people have back pain and discomfort and PT, rest, meds, often subsides the pain and surgery is not needed. Bout of sciatica that is constant for more than 6 weeks needs more attention to determine the reasons for the constant pain. Bulging discs can heal themselves over time, some do and some do not. Many have bulging discs that cause no pain.. and again some are unlucky and it is a painful disaster.
If you do not improve as your therapists states, you need to seek further treatment from a reputable spine surgeon to determine what else could be going on and other forms of treatment to attempt to easing your pain.
You do need to be careful about bending, twisting and lifting right now. You want your back to continue to heal if possible so you can go about your normal lifestyle. Give you back the time it needs, it's worth it.
Hope you continue to improve and dont need further treatment. Take care. Tammy