There are several considerations. The redness at the tip of the penis could be balanitis (inflammation that is more prone in uncircumcized penises), as well as other infections such as herpes or chancroid.
A GU source of the pain can be due to prostatitis which can cause the discomfort you are describing. A digital rectal exam and possible transrectal ultrasound can be considered for further evaluation.
The dull ache in the scrotum can be due to any number of scrotal masses (i.e. cancer or a cyst), as well as an infection. The test to consider would be a scrotal ultrasound for further evaluation.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
Medical Weblog:
kevinmd_b