Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with your doctor.
Without the ability to examine to obtain a history and examine you I can not provide you with a diagnosis nor recommend treatment. However, I will discuss with you the possible causes.
The problems that can cause groin pain can be divided into muscular causes, nerve causes, and bone causes. Also, hernias can cause groin pain, I will not discuss hernias though.
Muscular problems are generally due to strains. There is a group of muscles that move the leg inwards (what is called adduction). These are called adductor muscles and a sprain in them can cause acute groin pain. These strains are often due sports, or certain movements during lifting heavy objects. Physical therapy is the best treatment for this condition.
Osteitis pubis is a painful condition characterized by pain over the symphysis pubis (the bone that connects the two hip bones).
A small fracture in the symphysis pubis, a stress fracture, can occur with minimal trauma and can lead to groin pain. Problems in the hip joint can also cause referred pain to the groin. There are other muscular and orthopedic causes of groin pain.
Nerve entrapment can lead to groin pain. There is usually associated sensory loss or muscle weakness depending on the nerve entrapped. The most common cause of nerve entrapment is entrapment in a nerve in a bundle of tissue or muscle. Nerve injury can also cause similar symptoms. Problems in the spine or the nerves as they exit the spine can also cause pain. Tests called electromyography and nerve conduction studies may be helpful in making the diagnosis and localizing the site of the nerve injury, and may assist in differentiating spinal from peripheral nerve injuries. MRI is useful in diagnosing nerve root compression. Diagnostic blocks will often confirm the diagnosis of peripheral nerve injury. Surgical exploration with decompression and/or neurolysis (release of the entrapment) is sometimes necessary.
Radiculopathy, a problem of the nerves as they exit the spine, can cause hip and groin pain with pain the anterior (front part) of the thigh.
If the illioinguinal nerve is entrapped, it causes pain around the suprapubic area and in the groin.
Entrapment of the pudendal nerve lead to groin pain. Symptoms include burning, tingling, electric shocks, numbness in the anal region and perineal area (around the penis/scrotum or clitoridal/labial regions). The pain gets worse in the seated position. There is usually no objective sensory loss on examination. Pain is often relieved by such positions as sitting in the toilet. IF THE PAIN GETS WORSE WITH STANDING OR WALKING, THE DIAGNOSIS IS UNLIKELY TO BE PUDENDAL NERVE ENTRAPMENT. A varied technique of the EMG, called electroneuromyographic (ENMG), is often performed based on needle electromyography and the study of sacral reflex and pudendal nerve motor nerve responses.
Thank you for the opportunity to answer your questions, I hope you find this information useful, good luck.