Re: Back Pain
Welcome to the board.
Do you recall what dosage of antibiotics you were on and also how long you were infected before treatment was started? Lyme requires high doses (ILADS recommends 400-600 mgs of doxycycline) of antibiotics for at least 4-6 weeks, unfortunately many doctors have a lot to learn and undertreat the infection. If it is undertreated it can go dormant only to re-emerge later.
Also, ticks can carry Bartonella, Babesiosis, Erlichiosis, Mycoplasma, and others. Were you tested for any of these? Many people with Lyme also have one or more of these, and they must be treated in order for Lyme treatment to be successful. Left untreated these can cause almost as many problems as Lyme, and some can be fatal. Don't let any one tell you that these co-infections are "rare", they are quite common especially in certain areas.
It is possible that the pain you are describing is Lyme related.