Yes they can cause headaches.
A big misconception is that RF EMF cannot cause harm because it doesn't cause ionisation - the issue with this fallacy is that ignores other pathways/mechanisms for harm. Radiofrequencies, especially modulated/pulsed fields, cause oxidative stress, nitric oxide depletion, endothelial cell dysfunction, calcium ion channel leakage, even blood-brain barrier leakage.
Inflammatory responses can lead to headaches in some but not others. EHS is real - as real as light-induced epilepsy (visible light is non-ionising, but can still cause harm when pulsating).
Objective: We sought direct evidence that acute exposure to environmental-strength electromagnetic fields (EMFs) could induce somatic reactions (EMF hypersensitivity). Methods: The subject, a female physician self-diagnosed with EMF hypersensitivity, was exposed to an average (over the head) 60-Hz electric field of 300 V/m (comparable with typical environmental-strength EMFs) during controlled provocation and behavioral studies. Results: In a double-blinded EMF provocation procedure specifically designed to minimize unintentional sensory cues, the subject developed temporal pain, headache, muscle twitching, and skipped heartbeats within 100 s after initiation of EMF exposure (p < .05). The symptoms were caused primarily by field transitions (off–on, on–off) rather than the presence of the field, as assessed by comparing the frequency and severity of the effects of pulsed and continuous fields in relation to sham exposure. The subject had no conscious perception of the field as judged by her inability to report its presence more often than in the sham control. Discussion: The subject demonstrated statistically reliable somatic reactions in response to exposure to subliminal EMFs under conditions that reasonably excluded a causative role for psychological processes. Conclusion: EMF hypersensitivity can occur as a bona fide environmentally inducible neurological syndrome.
Read More: http://informahealthcare.com/doi/abs/10.3109/00207454.2011.608139
*EDIT to save commenting space, commentary from Prof Dominique Belpomme of ARTAC: http://www.emfacts.com/2012/01/electromagnetic-intolerance-elucidated/
"Dr. Belpomme’s team has developed a diagnostic method based on blood tests and a special brain scan (pulsed Doppler echography) to visualize blood flow. “These patients clearly have vascular disorders in the brain, said the oncologist. In addition, our biological tests show that 30% of them have high levels of histamine, 50% have too much stress proteins, most have low levels of melatonin (an potent anti-cancer hormone), and 30% have levels of antibodies and proteins that are tell-tale signs of thermal shock and brain damage.” He adds that half of his patients suffer from Multiple Chemical Sensitivity (MCS) and that MCS and EHS share the same brain abnormalities.
The oncologist explained that there are three distinct levels of sensitivity to pollutants. First, there is intolerance, caused by polymorphism. “This means that we are all different. For example, 30% of the population is most at risk of developing cancer.”
Second, there is the susceptibility factor demonstrated by Swedish oncologist Lennart Hardell who studied 16 families who were electrosensitive because of shared genetic factors. There are also active susceptibility factors, “such as dental amalgam that behave like antennas capturing airwaves”, explains Belpomme.
Finally, electromagnetic hypersensitivity appears in two stages. “The first phase is induced by exposure to a specific EMF frequency, either an acute or chronic exposure, such as talking on a cell phone 20 minutes every day. The first signs of hypersensitivity are pain and a heat sensation in the ear. In the second phase, the disease sets in. That’s when you become intolerant at all frequencies.”