By back trouble, I assume you mean that in the past you had a slipped disc, pinched nerve, or other lower back pain problem. Given this personal history, I think it is highly likely that the new symptoms you are having are likely a recurrence of the same or a similar problem. Unfortunately, people who have had a history of back problems
are likely to experience multiple flares of the same problem over the course of many years.
The symptoms you are describing, of numbness
or a tingling sensation in the legs are fairly consistent with a pinched nerve, for whatever reason, in the back. The fact that you also have weakness of the legs is concerning, because this might indicate the the pressure on the nerve is quite significant.
I think, therefore, that it is absolutely essential for you to see your primary care doctor
right away about this issue. Alternatively, if you were already followed by an orthopedic back specialist in the past, you could make an appointment to go back to see them. They can examine you to see if you have objective signs of a back or nerve problem and, if so, they may want to get additional testing, such as an MRI of the back, depending on how severe the symptoms are.