What support is recommended for women having nursing problems?

Please ASK. The best thing you can do for you and your baby if you have nursing problems is to ask for help and support! start with your pediatrician, obgyn, labor nurses and local lactation consultants or laleche league. Many town health departments or wic offices can direct you to resources. Enlist the emotional support of your partner and mother or support person as well. Other breast feeding moms too!
Nursing hot lines. Most hospital have nursing hotlines staffed by lactation specialists who will try to help you. There are also lactation consults who will make home visits and measure your milk production the baby's weight gain and your nursing techniques. I think la leche league is still around for this purpose.
Lactation consultant. You may find a good lactation consultant can help you with your nursing problems (even over the phone!) contact the hospital where your baby was born as you may be able to obtain good advice from the lactation consultant there. Also, your pediatrician may be a good resource for you, so don't hesitate to contact his/her office. Lastly, your local la leche league may be a resource for you as well.
Pediatrician. Pediatricians feel very strongly that breast is best. They can provide lactation support for moms who are having difficulty, or refer you to a lactation consultant. Ideally, you had a prenatal consultation with your pediatrician, and discussed breast feeding, had a breast exam, and were guided in what to expect with nursing. See your pediatrican even if attend the birthing/breastfeeding class.
Breastfeeding consul. Getting a consult with a good breastfeeding consult team and having good direct and phone contact with them. Also, some pediatricians are very good with this topic as well. Mom's should start with the pediatrician and seek of a good breastfeeding consultant team for help. Experienced friends and family can often also offer good advice and support.