Even if there in no pain now, you are prone to get lower back pain. Pain in upper thigh may be symptoms of what your reports shows. Need to consult a good physiotherapist who can take your spine assessment and prescribed you good exercises.
Next Steps
Find near by physiotherapist and start doing exercises under observation at list for a month.
Health Tips
Dont allow your weight to increase, if you already have heavy built try reducing weight basically from your tummy area.