Am I on right treatment for body pain?

The profile which you have given, it seems that you might have strptococcal infecrion, or simple viral infection. ASO titer at your age is non specific. Your doctor might be thinking about rheumatic fever, but you don't have that, hence you don't need the prolong course of penicilline, 07 days course which you have already taken is enough. If your aches and pains are still continuing, then meet rheumatologist to work out the exact cause of your problem. If you dont have any symptoms now, consider yourself cured, no need to continue any medication for raised ASO titer.