Thanks for your query Based on the facts that you have posted It appears that you have Varicocele
on left side.However this can be confirmed only on clinical Examination and Colour Doppler study of the scrotum
Consult qualified Urologist
for evaluation and to confirm the diagnosis.
As regards pain in testicle it is not related to your gaseous distension of bowels.but most likely to be due to varicocele.The excessive production of the gas could be due to eating excessive meat.
Take some enzyme preparation for digestion of meat.or restrict taking it