Welcome to the forum. Since you are suffering from a week it can be due to muscle strain
or some injury
that you have had unknowingly. It can also be due to groin pull during exercises or whiile performing any other activity. Avoid picking up heavy weight.
Pain is a sign of inflammation but you have not complained of any swelling, lump or enlarged gland. Get clinically examined to rule out any hernia
or torsion of the testicle. Some anti-inflammatory medications will give you temporary relief.
You may need a scotal lift and rest. Since you have been suffeing since a week do not neglect, take care.